I have seen a lot of blogs posting their favorite iPhone or iOS apps which seems to make sense since there will be a lot of new owners of iPhones and iPads after the Christmas and Hanukkah holidays. So in the spirit of sharing I decided to post links to a few of the apps that I really like and use regularly.
iPhone Only
Camera+ - $0.99 - This is a nice alternative to the native camera app. It has a timer, a grid (for taking level photos), and various scene and cropping tools. Also allows for sharing multiple photos on Facebook, Flickr, email and more. A recent update, including geolocation support, has made this app much better. It's important to know that this app does not apply to video.
AccuWeather Weather - Free - Much more visually appealing and informative than the native weather app. A recent update includes annoying video ads but they can be skipped.
Skype - Free - Skype just added video calling yesterday and that makes it much more useful than before. This app allows you to cut down on your minute usage on the phone and now will even let you do video chat with someone sitting at a computer or on another iPhone 4 with Skype.
Google Voice - Free - If you sign up for a free phone number with Google Voice this app extends the features to your iPhone. You can't totally bypass the core phone features and use Google Voice for everything but you can do many things, including listen to your messages and send texts from your Google Voice number.
Red Laser - Free - This app allows you to use the iPhone camera to scan barcodes on products and compare prices with local and online stores. You won't find all products in their database but this app has saved me from purchasing things that I could find much cheaper elsewhere.
iPad Only
Magic Piano - $0.99 - Play piano using an on screen keyboard or by tapping flashing lights. They have a song book that includes some very classic piano pieces. Kids and adults will love it.
ABC Player - Free - Stream ABC television shows (with commercials) to your iPad.
Amazon Windowshop - Free - Amazon.com re-invented their website for the iPad.
Weatherbug Elite for iPad - Free - A very nice ad supported weather application.
GoodReader for iPad - $2.99 - This app makes the iPad infinitely more usable. You can save many different document types (including PDFs and Microsoft Office files) for reading later. You can also access your Google Docs files for viewing. My favorite features are the annotations and searching withing PDFs.
Reeder for iPad - $4.99 - If you use Google Reader then this is an app for you. Syncs with your Google Reader account and offers many content sharing options as well.
The Wall Street Journal - Free - Although the app is free a yearly subscription fee is required to get full access. If you don't mind paying I think this is a very nice rendering of the paper.
iPhone and iPad
Kindle - Free - Amazon has the best e-book store and the best e-book app. This is better than Apple's iBooks because you also can read your books on your computer and now even lend books to other people.
Twitter - Free - If you use Twitter then this is the best app to get because it's free, works across iOS devices and is very nicely designed.
Netfllix - Free - This is a must have app if you are a Netflix subscriber. Even if you don't use it to watch movies on the iPad it's the best way to manage your queue while sitting in front of the TV.
Flixster - Free - A nice companion app to Netflix, since it allows you to search for and add movies to your queue. Also a good app for non-Netflix users who want to search for movies, rate them and share the ratings. Connects nicely with Facebook.
Jump Desktop - $14.99 - Perhaps the most expensive app you will ever purchase. It really opens up possibilities for your iPad though. Jump allows you to connect and manipulate your Windows PC over the internet.
Air Video - $2.99 - This solves one of the most frustrating limitations of iOS. If you have many movies encoded but not in an iOS friendly format (such as .wmv or .mkv) this app, along with the companion desktop app, allows you to stream video to your device with conversion happening on the fly. This has worked very well for me and even supports subtitles.