I was running the x64 version of XP for quite a while as to be honest I felt it much quicker than x86 and the performance difference was that great but one thing that annoyed me constantly was the lack of flash and java for x64. Everytime I went to a website that used them I had to revert back to the 32bit browser and I found that really annoying. Have Adobe and Sun released new players for x64 yet?