Apps I use:
Starbucks (finds them in whatever town I'm in)
Comcast (tv guide - even though I don't have cable)
RunKeeper
iTrailMap (download trail maps from ski resorts)
Metronome
Minesweeper, Sudoku, and Solitaire
Free Wi-Fi Locator
NPR News
Pandora
Fandango
Falling Balls (game - these balls fall out of the sky, you have to tilt the phone to make the guy on the ground run out of the way or else he gets squished)

And I'm perfectly happy with games/time suck, since I get bored when I fly and I fly a lot. Someday I'll actually invest in an iPad.