I have an AST Adventure 4066D for my old MS-DOS games I still have. (MS-DOS 6.22 and Windows 3.11)
A PIII 866MHz microprocessor running Debian 4.0 or Slackware normally, but exchange the HD with another one with Windows 98 for my Amateur Radio stuff when I need to.
An custom built AthlonXP 2.4 GHz microprocessor running Windows XP for my online flying/games. When not using it for games I have a hard drives with Fedora 9 and FreeBSD 7.0. Testing box for my different Linux distros I have also.
The wife and I run both Toshiba P-4 laptops running Microsoft Vista for internet surfing and general use.