In the past, we took a look at some of the best iPhone app interface designs. Since then, more and more applications are coming out that continue to impress us. This certainly isn’t an end all list. There are plenty of gorgeous apps out there and no way to cover them all!

You may even seen some apps we’ve covered in the past, but with the App Store constantly growing and changing, software is constantly being updated and their interfaces improved. Here’s a look at some of the sexiest iPhone apps out there!

Squarespace (Free)

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Squarespace’s great iPhone application is a companion to their high-quality premium publishing platform. You can manage and create posts, upload photos and view statistics for your site.

Squarespace

Tumblr (Free)

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Tumblr’s app lets you do almost everything you can do on their website. Post text, photos, chats, videos and more. View your entire dashboard in an iPhone-optimized layout and even like and reblog posts.

Tumblr

Square (Free)

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Square is a fun new way to quickly and securely accept card and cash payments anywhere. No need for a merchant account of fees.

Square

Outside ($2.99)

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Outside is a unique way to view the weather – just look out the window. Outside combines weather forecasts with push notifications to let you know when to bring that umbrella with you!

Outside

Articles ($2.99)

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An Apple Design Award Winner, Articles is a gorgeous Wikipedia tool, allowing you to read and discover articles in a stylish way.

Articles

Instapaper ($2.99)

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Instapaper lets you take the web with you, allowing you to easily save pages for offline reading. Instapaper optimizes your articles for reading, taking out graphics, page navigation and giving you just the content you care about. A free version is also available.

Instapaper

Consume (Free)

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Consume lets you keep track of usage on your mobile phone, wireless card, phone cards and more. With over 100 providers and 10 supported countries, Consume can help you keep your mobile usage in check.

Consume

AppAdvice ($1.99)

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AppAdvice does like their name suggests – give you advice on applications. Whether you’re a brand new owner or a seasoned app shark, AppAdvice can help you find cool stuff to fill your iPhone.

AppAdvice

Keymote ($3.99)

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Keymote is touted as “the only remote you’ll ever need”. The app allows you to create custom key sets that act as shortcuts for your Mac applications. Users can create and submit keysets for any application with popular ones available for programs such as Safari, Photoshop and Front Row.

Keymote

Byline ($4.99)

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Byline is one of many available RSS readers available, but is notable for its automatic Google reader syncing and offline reading ability. A free version is also available.

Byline

Pennies ($2.99)

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Pennies is a super simple money tracking app. Utilizing a simple interface, Pennies treats your account like a gas tank, showing you when you’re spending is too great and you are nearing empty. Quickly add expenses as they occur and export your data.

Pennies

MiniBooks ($14.99)

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MiniBooks is a companion app for FreshBooks, a complete invoicing and billing solution. Sporting all the abilities of the website, the application helps you bill clients, track payments and even keep a log of time spent working on sites for invoice purposes. A “lite” version is also available.

MiniBooks

Delivery Status Touch ($4.99)

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Delivery Status Touch is an elegant solution to tracking the status of almost any package or order. With support for over 25 popular services and shipping companies, Delivery Status Touch is sure to keep you on track. A Mac dashboard app and a web sync option help keep packages tracked across multiple devices.

Delivery Status Touch

Sally Park ($0.99)

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Forgot where you parked? Sally Park is a gorgeous app that utilizes your iPhone’s GPS and compass to quickly find where you parked your car.

Sally Park

Loopt (Free)

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The developers say it well themselves, use Loopt to find out who’s around, what’s to do and where to go. An interesting mix of social networking, location-based check-ins and reviews, Loopt is sure to make daily life exciting!

Loopt

Tripmix ($1.99)

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Tripmix is perfect for listening to your music on those long road trips without the hassle of sorting through playlists and deciding what songs you want to listen to. Tripmix picks an artist, plays a few songs from them and moves on.

Tripmix

On This Day… ($1.99)

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On This Day… is a stylish historical calendar that lets you look at events and birth dates from the past on your iPhone made by the same folks that brought you Articles.

On This Day

Billings Touch (Free)

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Another Apple Design Award Winner, Billings Touch can be used as either a standalone application or as a companion to the full featured Mac desktop application. Billings keeps track of almost everything related to time tracking and invoicing.

Billings Touch

iStudiez Pro ($2.99)

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If you’re a student, you should have already downloaded iStudiez Pro. The beautiful application helps you take control of your schedule, juggle classes and assignments and manage your grades.

iStudiez Pro

1Password ($6.99)

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If you own a Mac, you should have heard about 1Password by now. The award winning and highly praised password management tool comes to the iPhone. With Wi-Fi syncing, you can keep all your passwords, credit card information and sensitive items secure and with you at all times.

1Password

AIM (Free)

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AOL’s popular instant messaging client comes to the iPhone. With an easy to use and intuitive interface, AIM for iPhone sports some cool features such as push notifications, Lifestream support and multiple accounts. An ad-free “Pro” version is also available.

AIM

Twitter (Free)

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In the past, we touted Tweetie as a gorgeous iPhone app, and after Twitter’s acquisition of Atebits, we took another look. Featuring all the great features of the premium version of Tweetie with a new free pricetag, Twitter for iPhone is only getting better. It’s arguably the most complete and best looking Twitter client out there.

Twitter

Osfoora ($2.99)

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Relatively new to the Twitter client game, Osfoora is a fast and clean client that has all the features you’d expect in a Twitter app and some ones you wouldn’t such as the ability to tweet songs, translation and color customization.

Osfoora

Twitterrific (Free)

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IconFactory’s Twitterrific has always been a great Twitter client. The first to support the iPad, they have been hard at work modernizing and simplifying their iPhone app interface and it looks great so far.

Twitterrific

TweetDeck (Free)

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TweetDeck takes organizing your Twitter feeds and information a step further. With groups, columns and tabs, you can see all your information such as trends, followers, feeds and more they way you want to.

TweetDeck

Birdhouse ($1.99)

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Birdhouse is another gorgeous app for Twitter that takes a slightly different spin on it. Use Birdhouse to collect your thoughts and plan your tweets for later.

Birdhouse

iMovie ($4.99)

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So being this app is direct from Apple, they might have an edge in the sexy interface competition but this one is too good to pass up. iMovie is Apple’s latest mobile application that does so much more than you’d expect. Shoot, edit and export HD movies quickly and easily. All you need is an iPhone 4 and this app.

iMovie

Snow Reports ($1.99)

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Snow Report gives you the ability to create a personalized report of all your favorite ski resorts worldwide. Imagine a weather application, tailored to skiing and snowboarding.

Snow Reports

Ramp Champ ($1.99)

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Ramp Champ is an absolutely beautifully designed spin on classic boardwalk games such as pinball and and skee-ball. With various levels and prizes to collect, you’ll spend hours playing this great and simple game.

Ramp Champ

Warships (Free)

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Warships is a fun twist on the classic battleships game. Play against the computer or other iPhones using your bluetooth connection. Warships lets you pick varying degrees of difficult and even thought about bragging rights, letting you tweet your score when you win!

Warships

The Font Game ($0.99)

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From the people behind I Love Typography, the Font Game is guaranteed to be the most fun you could have with fonts. If you are into typography, you’ll love this app’s timer based game of identifying fonts. It can get pretty challenging and looks great!

The Font Game

Orbital ($2.99)

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Orbital is a game with a very simple concept – use your cannon to destroy orbs of light that explode with fascinating color and effect. A twist on games like brick breaker, Orbital is challenging and fascinating to play.

Orbital

Flight Control ($1.99)

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What list would be complete without mentioning one of the most successful games available on the App Store? Flight Control, the incredible addictive air traffic control game continues to be updated and added to. Beautiful high definition graphics set this app apart from the rest.

Flight Control

Real Racing ($4.99)

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Another platinum hit from the guys at Firemint, Real Racing is an amazing racing application for iPhone. With high def graphics, and making full use of the iPhone accelerometer and vibration, Real Racing is simple to learn and fun to play.

Real Racing

Strategery ($1.99)

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Strategery is a modern, great looking take on the classic game of Risk. A strategy game involving the overtaking of colored land masses, Strategery can be played solo or other iPhones.

Strategery

Spendly ($0.99)

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When it comes to tracking your expenses and spending, Spendly may be just what you need. It is simple, straightforward and easy to use to keep track of where your money is being spent.

Spendly

Nota ($4.99)

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Nota is a set of useful tools for musicians at any level. It includes a piano chord and scale browser, a note locator, a note quiz and reference library with over 100 symbols. A free version is also available.

Nota

Barista ($2.99)

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Barista is all about making cafe-quality espresso at home. It’s a personal, portable tutor which will help you get the most of your espresso machine.

Barista

Put Things Off ($2.99)

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Put Things Off is a unique, laid-back todo list application that is designed for procrastinators and busy people alike. It’s a quick way to create notes and lists that allows you to put off stuff that isn’t immediately important.

Put Things Off

Interface ($9.99)

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What better way to end this list of gorgeous iPhone app interfaces with an app that creates just that! Interface is a great prototyping and mockup tool for the iPhone with some exciting features like a live view that allows you to simulate your interface before you take the time to build it.

Interface

Share Your Favorites!

Do you use an application that you think is really well designed? How important is the design of an application’s interface when you’re deciding whether or not to buy? Feel free to share it in the comments!