I use Windows 7. I once had a dual-boot on my laptop between W7 and Ubuntu.
Dual boot Win 7 and Ubuntu on my laptop, desktop has XP.
Desktop dualboot Win7 pro/Kubuntu
laptop dualboot Kubuntu / win 7 pro (haven’t booted win for months )
OSX, Laptop mostly.
Win7 on desktop, laptop is far more convenient for 99.9% of use.
Laptop (MacBook Pro) running Mac OS X (“Lion”).
As well as Windows 7 ( running under Desktop Parallels).
Works pretty good (especially for Automation).
Windows 7 Home Premium 64bit
Greetz,
Zeph