Media Center Mobo

I'm looking to build a new computer I'm not sure what Mobo I need. I'm going to be using it for Grad School Comp Sci, and I want it to be a capable media center.

I'm not sure if I should go for integrated graphic or not I don't want this machine to play games, I already have one that does that and I'm getting rid of it.

I want to stick with an AMD processor and Nvidia for video (CUDA)

I have 2GB of DDR2 800 laying around that I'd like to use

I don't need it to be small form either

I mean honestly my only motivation for getting nvidia is because I would like to mess around a bit with CUDA, and the more I look at it it seems that everyone is saying that it isn't worth messing with unless you have a good card. When it comes down to it CUDA is worth about $20 to me, so looks like I'm skipping it

I'll look around at the AMD 780Gs and see what's what