Window Vista Ultimate 32.bit!
Last year when I took part on Window Vista Ultimate RC1 from Microsoft, it was suck big time, Hardware and most of my software I use is unsupported, but early this year; It Become Superb! everything is fine, Some hardware still use the same driver from XP, as long as your using the same bit (32 or 64 bit).
Trivia: Sometime I miss window 1.0 use it back in early 90's. the computer was given by my uncle for us to play with while I was in London. Then Early school year, I experience window 3.1x. Back to my mother land, Brunei, I then continue to use window 95 and experience all window platform until Vista nowadays.. But NOW, I'm really craving for a Macintosh..