I'm using Windows 7, and believe me and everyone else that has already said it in this thread... it's better than Vista. It's what Vista should have been the first time through. Skip Vista and get W7 when it's out (I have a full version already because of my university). As for gaming - runs fine for me, I see no issues. I have yet to have any problems with any games that I've played on my pc.
EDIT: I would like to point out a few things, as I've gotten some messages from people asking about W7. If you have a computer that is running Vista, then YES, you can of course run W7. W7 takes up less space and runs way less processes. As for whether you want 64 bit or 32 bit, that's up to your needs. 64 bit is good if you intend on running more than 4 gigs of RAM and need to do stuff that requires 64 bit processing. This is because 32 bit operating systems can only really "see" a max of 4 gigs of RAM and will only use about 3.5. Also consider that some applications will not run or do not have 64 bit support. If you're an average user it's safe to stick with 32 bit. If you're building a beast of a machine to run games at max settings and such, go ahead and grab 4+ gigs of RAM and Windows 7 x64.