I decided to splurge and purchase this baby: The AsRock ION 330 HT for all my media center needs.
People seem to have got it working fine with Linux, except for the remote control... but I'll look into that.
Now, all I need is a TV (or monitor), and a keyboard+mouse for it. Time to head to Saturn and start evaluating TV sets.
Update: It arrived today, and I didn't have a keyboard nor screen for it... I've now bought a decent Samsung monitor and a cheap microsoft wireless keyboard+mouse. The TV can come in a little while - too big a purchase to buy under pressure.