Vista 64
I would like to have W7 64 but upgrading from XP did cost 140 euro's and soon after W7 arrived. Would again have to fork out 150 euro's. I can't keep up with the arrival speed of new baked OS's. Still i'm quite happy with Vista. Installed once in 2008 and still working fine. Never had that before with any OS, be it Windows or Mac.
edit: or Atari
