"...as I reluctantly creep to Windows 7 as a replacement for XP."
Win7 is fine and much stabler. Even Win8 is not too bad if you use
Welcome to Classic Shell
Mac/OSX is polished and (mostly) headache-free, though you need a Mac*
Linux Mint 14 KDE -
Main Page - Linux Mint - is very tasty.
FreeBSD -
FreeBSD 9.0-RELEASE Announcement - if you're really serious.
Mac
*yeah, I know about Hackintoshes - made one myself - not bad at all