I'm running the 32-bit version. I was going to go 64-bit but there's just no point yet. Drivers are more scarce and virtually nothing takes advantage *yet*. When I rebuild this PC in a years time I'll upgrade to Vista 64.
I've noticed no problems gaming on it either. Infact it's much better than on XP. I'm working my way through HL2 Episode One and have definitely not seen any issues re: AI or graphics! I'm on the part where you just encounter the strider in the train station, and trust me, his AI is spot-on (damn it).
I love the way Aero really uses the graphics card for rendering. Attached is a screen shot taken for fun mostly. I have World of Warcraft running, with maxed-out settings, I have Far Cry running (1.4) with fully maxed settings running in demo loop mode, there is also Photoshop, Firefox, MSN and my email client running. It did this without breaking a sweat. My dual-core CPU didn't push above 75%, although not surprisingly I was using 1.6GB of RAM! The fact of the matter is, it worked. No 'juddering', no 'slow down', it just works.
And I absolutely love the fact that when you tool-tip the taskbar, the visual tool-tips for games show the game window actually running in rea-ltime, as does the 3D alt-tab. Gorgeous
It's slick, it hasn't crashed yet, and with the very neat sleep/hibernate mode, it boots in 2 seconds.
Cheers,
Rich
Heavy on the Magick