The build list
So here's what's going into my HTPC:
AMD Athlon XP (barton) 2800+ (relatively cheap, and overclocks easily)
Gigabyte GA-7VT600 motherboard. (very cheap, but has all the goodies)
Hitachi Deskstar 250GB SATA driver (currnet top SATA drive according to storage review)
M-Audio 7.1 Revolution. (inexpensive audiophile grade sound card)
Fusion HDTV III PCI tuner (in time for March Madness)
ATI Radeon 9600PRO (inexpensive, but still pretty high-end video, with DVI out)
Antec Sonata case. (simple, black, relatively quiet.)
Add to that another WD 80gig IDE drive, CD-RW/DVD-ROM, wireless ethernet (until I run the Cat-5 down from the router) 512 meg of ram, and a giant copper heatskink (by Zalman)
I'm hooking it up to a 51" Hitachi HDTV via a DVI cable. This should give me a usable resolution of about 1900x500 (progressive scan, upconverted by the TV to 1900x1080i.)
Update: I just got Windows Media Center installed (XP with a few tweaks.) Holy shit, this machine is fast.