Core2Duo E8400 @ 3.6Ghz
Asus P5E
8 GB Corsair XMS DDR2
Sapphire Radeon 5850
Soundblaster X-Fi Gamer (had issues with the onboard sound)
Drives: Samsung 250GB, WD 500GB, Samsung 1TB + 2GB external drive for backups, Optiarc (I think that's Sony) DVD-RW
Screens: Samsung Syncmaster 226BW (22", 1680*1050) and an Acer screen I bought months ago for dual-monitoring and haven't even connected yet (21,5", not standing next to me atm)
beQuiet! straight power 550W
Enermax Chakra case
Logitech G500 mouse
IBM Model-M keyboard (the only real keyboard there is; screw you guys and your fancy G15s! ;-) )
Sennheiser PC-151 headset
EDIT: The system is over 3 years old now but still doing pretty well; only things I changed/upgraded were soundcard (as mentioned, issues with the onboard sound causing bluescreens), GFX card (originally a 8800GTS G92) and the DVD-drive as the old one broke due to me inserting the plastic cover from a DVD spindle along with a blank DVD. Oh yeah, and the G500 as my old G5 broke down about a year ago (mousewheel)