I stuck with Vista x64 for over three months. In the end there were a number of problems that I could not solve.
I decided to upgrade to vista x64 in March. The first problem I ran into was artifacting with my EVGA 7900GT KO. Here is a link to the problem. http://www.diskusjon.no/index.php?showtopic=718291
Sorry it is in German, but it has a picture of the exact issue. I RMAed the card and the 7950GT they sent me seemed to solve the problem. I did not have this issue under XP.
Most games worked flawlessly. Especially steam games like HL2, Counter-strike source and DOD:S. Fear was good too, along with C&C3.
That was until I wanted to play Battlefield 2. With all of the latest patches and drivers I could not play more than 30 minutes without it either restarting my computer or crashing to the desktop. I researched the problem for over a month without being able to resolve the issue.
I tried such things as:
Setting Processor Affinity
Large memory address mod of the bf2.exe
loosening timings on my ram
trying a SLI certified enermax ps
and a bunch of others that I cannot recall at the moment.
I also noticed the game was much more choppy in vista than under XP.
Another annoyance was the extremely long boot times. I can boot into XP in way less than a minute. Vista would take anywhere from 2-5 minutes to boot. All of the forums I explored could not explain this, nor could they give a decent way to solve the problem. I checked around with the system event viewer without gaining much information. To be fair, upon first install the computer would boot in just over a minute. Later, the only programs that were running at startup (other than standard system services) were Avast, the vista sidebar, and 2 mounted ISO drive images from Alcohol 120. Maybe it was alcohol? Or maybe a driver? Disabling it wouldn't help though. But I enjoy not inserting a game cd when I want to play. Id rather mount the image.
Consequently, I am back to XP and happily playing BF2 on high full at 1920x1200 for hours without a problem. I really enjoyed the vista look, but I am going to wait a little longer before giving it another go.