Building a computer for a home theatre

I"d like to build a computer to completely run my theatre. Sound, video, and my games.
I like the AMD64x2's, but don't know about the mobo, but it'll be getting hot, so i'll want to be able to either oc or downclock, depending. Even if it's just messing with the settings.
Custom made case.
GOOD DVD drive.
win xp pro or win media center?
graphics? I don't do really heavy gaming, for now, but i do game. Also, the res. on the projector will be a sxga (i think) but basically plenty for even my current radeon 7500 res. wise. Anything else i'm missing? Oh yeah, keyboard and mouse. And gigabit ethernet. I'd like sataII as well.
Thanks guys