Right now I have Angry Birds, Cut the Rope, Fruit Ninja HD, Hex Defense, Chalk Ball, Doodle Jump, Jewels, Peggle, and Plants vs. Zombies installed.
I think the challenge is finding games that look decent on the tablet. Peggle and Plants vs. Zombies don't look the best, they aren't awful, but not as good as they could be. Most of the other ones I have installed look pretty good.
Dungeon Defender, Galaxy On Fire 2, Vendetta, and Angry Birds Rio. The Tegra Zone has a good list of games designed specifically for our T2 chips. You can find it in the market. They also have a video demo of the Kalel Prototype quadcore chip. Insane graphics capability!
Samurai II vengence, ive wanted to play it on my playbook sooo much. But not until the emolator comes. But its beautiful on the samsungs wonderful screen. Well worth the money spent, but im having issues with the movement. The orb thingy becomes unresponsive for two or three taps. But still a great game.
I got introduced to Konas Crate from Androidcentral so I tried out the lite version. I got hooked right away and bought the full game (only costs 99 cents!). This is the best dollar I've ever spent on an app.