Like gg, I'm running W7 64-bit. Decided to try 64-bit version when I rebuilt the machine knowing that I could switch to the 32-bit version if I needed to.
No problems at all. Can't say if it is all faster/better/superer but Photoshop 64-bit certainly feels fast - but this is based on nothing more than an unscientific gut feeling. Don't do games so I can't offer any thoughts.
The only hardware snag has been with HP devices for which drivers were not available for a long time - but that related to W7 rather than 64- or 32-bit issues. For older software, including drivers, the way that W7 seems to handle compatibility management seems very good - I think MS has finally got it right.