Match 3d flick puzzle thingy has a pretty nice soundtrack, although i'm not sure if it's only one track
Blimp is frickin' chilling. Evertime I listen to it I get goosebumps. And awesome! I thought only Zen Bound's music was downloadable. Now I get EDGE, too!
Edge SweetWater Defense (I really like that one) Doom Resurrection The music of the start video and the credits and the main menu in Real Racing NFSU Space Invaders: Infinity Gene
Nobody has mentioned Glyder yet -- the soundtrack is also available for download. As for pulse-pounding soundtracks, it's hard to beat SI: Infinity Gene -- feels like you're getting a workout.
iBlast Moki is still in development, but the music for that game is made by the same guy who did Edge, so it's bound to be good! Check the trailer out in the Upcoming Games board, as that has a taste of the music!
I vote for the loop in PewPew. It gets stuck in my head all the time. edit: adding the theme to Galcon
Hero of Sparta, Rolando 1&2, Payback, Bejeweled 2, Carjack, Cube has a couple good ones, Motochaser has only three songs but they are all good, Minigore music rocks. And that' all I got for now.
Up There The piano pieces by Will Tuttle in the game "Up There" are pretty good - I bought his album after playing this game
There is a lot of memorable music, but here are the ones which stick in my head and are original on the iPhone (meaning no Monkey Island, although the voiceovers are fantastic). Rolando 1+2 Zen Bound (Listen to the soundtrack as a standalone all the time) Space Invaders Infinity Gene Star Hogs Edge... but only when I am playing the game.