Thanks to Bug Blatter for the following Google Nexus 7 game recommendations-
First the obvious ones: Riptide GP and Shadowgun THD. Both nicely optimised for T3 and the first games I installed.
Dark Meadow looks great, although I found the gameplay a little repetitive. Apparently it gets better if you go further.
Apparstus looks great, altough it's not T3-specific. There's a free Lite version.
Grand Theft Auto III and Max Payne are pretty much like the original PC/console versions.
Demolition Inc is cute and T3-optimised, although not exactly a tour-de-force of what the T3 can do.
NOVA 3 actually looks and runs better on my S3; Gameloft hasn't optimised for T3. Some effects are missing (e.g. smoke) and it's a little jerky. Still worth a try though.
Mass Effect Infiltrator is fun and looks great. I don't think it's T3-optimised but looks great anyway.
Puddle THD is a bit of fun and looks pretty good - it's T3-only.
Zen Pinball THD is great if you're into pinball at all, again it's T3-optimised (might be T3-only).
And last but certainly not least there's Dead Trigger. Looks great and is a lot of fun to play. It's pretty heavily T3-optimised. I've gone a fair way without resorting to in-app purchases. There are hacks using GameCIH to give you free money, gold and XP.
Sonic II is T3-only (although the non-T3 version may also be out by now). Works very well and apparently looks closer to the console versions than any other mobile platform, although it's not my kind of game.
To get the most out of many of these games you really want to use a controller. I use my PS3 controller wirelessly and it works brilliantly. For many games no additional app is needed, for others SixAxis is required. TegraZone tells you which titles have native controller support.