There's hardly anything in terms of free games, so I haven't bothered. I usually require a lite version to try a game first before buying it, and there ain't nothing of interest like that yet.
The free air hockey is good for what it is. I like that Shanghai Mahjong upgraded it's app to be iphone and ipad compatible, so you get HD without buying another app. The only app I've double-dipped so far is Lets Golf, the graphics look better and it was only 4.99, so what the heck. My only new HD game I've gotten is I gave super shock football a try for 3.99, the graphics and sound are great. It's not super deep, but it's fun enough.
Aurora Feint 3 - match-3 game/RPG. Great in concept and beautiful to look at but one of the strategies is to turn the iPad to change how blocks fall. Works like a charm on the iPod, but can become cumbersome to do on the iPad.
Words With Friends HD - this is the only game I've paid for so far. It's a Scrabble clone that is ten times better than EA's official Scrabble app. The big draw for me is that you can create games with other random people around the world who are looking for a game.
