I have two computers that sit side-by-side. I actually use my older one more often.
Windows2000Pro SP4, 128mbRAM, 30gb HDD, 64mb nVidia GPU.
My better computer is used mostly for DVDs and music, looking forward to getting WoW or something.
Windows XP Home SP2, 1024mb RAM, 2x120gb HDDs, 256mb ATIx800Pro
I actually prefer Win2kPro over any OS I've used. So familiar, it doesn't hog ram and its quite stable. ;)