Alienware M17x R4: Windows 7 x64 Home Premium School and portable gaming and work rig, upgraded to 16GB of RAM
DIY desktop: Windows 7 x64 Home Premium Main gaming and work rig, water cooled, planning on upgrading the RAM and CPU/mobo
Acer aspire one 721: Windows 8 x64 Professional (with media center upgrade since it was free) Crapy laptop which is only usable for word and some light internetting
Really old brandless pc: Windows XP x86 (home edition?) only still have this one because I use it to test my water cooling loop with it's molex power\
I don't realy like Windows 8, IMO it's just too focused on touchscreen pc's and I don't realy like those :/ Metro is forced down your troth and I would have liked to see it as a option :/
Windows 7 is THE OS I like, it could be better with some upgrades that are in Windows 8 (Things like build in ISO reader and some parts of the new task manager), it's customizable enough for me, as I don't want to hassle with codes too much.