Since everybody's posting their keyboards, here are mine.
The first is an IBM Model M, revision 1391401 with a detachable PS/2 cable and manufactured in 1989. This is my primary keyboard for the desktops.
Next is a partiallyworking no-name PS/2 that I occasionally need to use for headless PCs. The left Control, left Shift, and quote keys don't work on it.
The black one is a Micro Innovations keyboard I got off Newegg for $1.99 and use in situations where I need to use a fully-working keyboard but don't feel like moving the Model M. The O and I keys sometimes repeat, but I can live with that.
Underneath is a no-name PS/2 keyboard I used to use for Frets on Fire (note the colored-in keys). This keyboard is completely dead and doesn't even have a cable left in it (I used it for scrap wire).
I also have a Mitsumi AT keyboard (not pictured) that I used with an old Pentium-120 machine that I no longer own.
The top mouse is a Microsoft Serial Mouse 2.0A, and the bottom one is a Genius NetScroll Plus PS/2.
Of note, I don't own any USB keyboards or mice.
UserAgent: Mozilla/5.0 (Windows; U; Windows NT 6.0 x64; en-US; rv:1.8.1.11) Gecko/20080102 BonEcho/2.0.0.11 (mmoy CE K8C-X05)
Laptop: HP Compaq nx6325 - Turion 64 X2 @ 2GHz, 2GB DDR2, 100GB HD, ATI Radeon X300, 15" LCD, Seven Pro
Handheld: Palm Treo 650 - Intel PXA270 @ 312MHz, 10MB RAM, 32MB flash, 2.7" LCD, Palm OS 5.4