I'll throw mine in the mix, but it doesn't really measure up to some of the firepower already posted... *drools*
Case: Cooler Master Centurion 534 Black
CPU: Intel Dual Core E2180, oc'ed to 3.0 ghz
CPU cooling: Akasa AK-965 fan
GPU: 8800gt 512mb (whoo!)
Mainboard: Gigabyte GA-P45C-DS3R
Ram: 2GB OCZ Platinum (I've got to get another 2 gig of this tbh)
HDD: 250gb Western Digital Somethingorother
Optical: standard dvd-rw. I'm lead to believe it's IDE o_0
Mouse: was a £5 logitech, now a MX518
Keyboard: G11
Monitors: 22" LG-dunno-what that's also a TV with freeview. it has horrible sound and no headphone slot
OS: Vista home premium x64
Power supply: was some old cooler master cheapo with a crappy fan, replaced it with a corsair 450w and <3 it
Speakers: Logitech X-140 (great for the price)
Mic: no idea, something cheap headset again from logitech. I don't use the headphones, just the microphone.
as well as wireless adaptor PCIe card and a PCIe card that gives me more usbs, which I didn't need to use cos the motherboard has loads as it is.
oh yeah, runs tf2 at solid 60fps with everything maxed.