Share your experiences of applications that you feel work well and have absolutely beautiful UI's. The ones I have found so far are listed below. It would be great to get some nice replies on this - stunning apps on a stunning phone = priceless.
Apps I feel work very well and have awesome UI's:
Craigslist Mobile Pro (also free version)
DocScanner (decent UI - could be better)
GarageBand (not iPhone but awesome interface)