Will's HTPC

Hardware

2.4ghz P4, 512MB Ram, onboard NIC
ATI TV Wonder PCI
NVidea GeForce4mx
NEC-1300A DVD-R drive
Turtle Beach Riviera (For optical out)
80GB HD
IR Keyboard

Software Configuration

Windows XP Pro
Powerstrip - to create 1280x540 resolution
DScaler for viewing scaled S-Video
VLC player for playback of videos and DVDs
85% of the time I use DScaler, so it just sits there.
XLobby is a nice front end, but it's time consuming to really configure

I'm now building a MythTV frontend in another partition of the drive. This way I can take my time and not stress over Myth not being configured.
myHTPC Howto
Interesting Software:
Media Portal
Media Portal - looks pretty interesting, but appears to require ALOT of overhead. Throw enough hardware at it, and you can pvr HDTV. I wasn't too impressed with the dvd player. It would NOT run fullscreen. - the screen would be blacked, but it was the resolution of the original windowed program.

Got all media
Another promising front end. I think it trys to do too much.
But it does perform better on less hardware than mediaportal.

Dscaler
DScaler/Dinterlacer is AWESOME. It takes a signal from your capture card and de-interlaces it. This REALLY improves the video quality. Thanks to this I have VERY smal scan lines with standard TV.

VLC Media Player
A FANTASTIC player. This thing plays almost anything and EVERYTHING you throw at it. There are a few windows media player files it will choke on. But DVDs, Mpeg, divx, etc play happily.