i use windows 7 ultimate 64bit
for those of you who are too chicken to get windows 7 know this
before i was adamant about sticking with xp, then i used win 7 at school
i loved it, i quickly installed it on MY old computer (2003 intel celeron D 2.6GHZ processor)
and much to my amazement it actually ran FASTER with windows7!!!!!!!!
not to mention i have had less problems with windows 7 then with win XP
windows 7 and vista are almost NOTHING alike
if you were disappointed with vista you will be thrilled with windows 7