So many to choose from... Its a tough call between pocket go [EDIT: d], minigore, doodle jump, orbital, run!, 33rd division, boom brigade and mr aahh. If i had to choose one id probably pick 33rd division but its really close.
I'll through one in the mix...The Deep Pinball Most realistic pinball game to date. I think there's a lite version out now.
ill just list my favorite $1 games: -Pocket God [just a great game] -Samurai: WOTW [undiscovered gem in the appstore, seriously] -GD Swarm [fun if thats ur kind of game] -Unblock Me [simple, but fun, and thousands of puzzles] -Alien Glyphs [really fun once u get used to it] -9000BC [really good game, very active dev] -Dotopop [simple, yet so much fun way better than Chain RXN] -Minigore [fun..but after awhile..meh. after more updates it'll be good] -DoodleJump [just a good time-waster]
Well, it totally depends what you like. Right now two of my favorites are highly unique match 3's with well-balanced timed modes, Buggle and Cash Cow. My personal favorite puzzle game is Fling.
Thirty One! I had to mention it It was voted number 1 card game in Camzy's thread: http://forums.toucharcade.com/showthread.php?t=31502
Soul Card master, Alive4Ever, MiniGore. I bought some more on sale too which I do like, but I've almost finished A4E (and it was the first game I bought, back in Sept), and Soul Card Master has some CCG charm under all the translated text and lack of explanations on card mechanics.