1. Omnifocus- I use this app to keep track of all my tasks, this app stands out because it does over the air syncing to the Mac and iPad.
2. Beejive IM- I use this app to communicate with my friends, this app stands out because it has a really nice interface and it's solid, and FAST.
3. Documents to Go Premium- This really helps me edit office documents. After it's update to version 4.0, it's fast and has a newly designed interface. The big feature this app has is the ability to open files in Dropbox, iDisk, Google Doc and edit them then save them back to the cloud.
4. Awesome Note- A really beautiful notes application that syncs with Evernote or Google Docs. A feature I really like is the ability to use iOS 4's multitasking feature and sync the notes in the background.
5. Atomic Web Browser- This is just simply a browser. But it's so good that I use it instead of Safari. It's got multitouch gestures to navigate,full screen mode and really, much much more.