Not got as many games as i used to have unfortunately but scrounged round a few mates for logins and tried out the following:
Diablo 3 (OSX native) runs fine at mostly high settings (shadows and a few others turned down and dropped the resolution to 1680x1050 to give it a helping hand). Wouldn't have any issue playing it on here.
World of Warcraft (OSX native) hovers around 60fps on good settings with the same resolution. More than playable but it does heat up a hell of a lot and the fans are at full tilt within 3 minutes or so. Checked on istat and the cpu is hitting 95 degrees after 10 minutes just standing around so wouldn't fancy playing it for any decent stretch without some sort of cooler.
Eve Online (OSX native) runs fantastic, best one i've tried so far, although it's pretty well optimised these days so i was expecting good things. Didn't get chance to jump into any big fleet stuff (been ages since i've played so didn't fancy messing around too much on my mate's account, but the few missions i jumped in ran perfectly, over 100 fps in some areas on reasonable settings)
Bootcamp'd over to windows i've tried the following which all run fine: TF2, CS:GO, Saints Row 3, Minecraft (presume this also runs fine on OSX, i had it on my windows image so figured i'd try it while there), Anno 2070 (bit choppy when there's a lot going on), Dawn of War (various expansions), Age of Empires 2 (hell why not??).
Staying on windows:
BF3 - runs ok, depends on what level of quality and fps you're willing to accept. If you're doing competitive multiplayer then it's not the machine for you, but if you want to play a bit of campaign mode or something then it'll be fine.
COD - Only had 4 installed but figured seen as they're all the same it should be a good indicator - worked fine, as with bf3 it depends what settings you're willing to play at and what you expect from a laptop with no dedicated graphics card.
Skyrim - Surprisingly fine, even with middle of the road settings i was getting 35-40 fps from it. Laptop did start kicking out some heat after a while (seems to be the done thing with the big 3d rpgs for some reason, but it wasn't as bad as others)
As for stuff that didn't run so well:
I tried out FFXIV just to see what happened with it (not expecting much). It did run and got to about 20fps on low settings, for me it's not ideal but at a push it's playable (as long as it's nothing too intensive / reaction dependant).
BF4 - as someone else has said, near enough unplayable, lag all over the shop, textures cutting in and out. Saying that it gives my PC a headache which has got a decent graphics card on board so I wasn't expecting miracles.
Hope some of those help anyway, spec sheet is below if you need it. Not a gaming beast by any stretch, but pleasantly surprised with some of the games it managed to run!