if it's only going to be used for video playback then you don't need a video card at all, get a shuttle with onboard video such as the G3/G5/G6 series... or if you want HD acceleration get a 8500 GT or similar. if you're going to be putting in an 8800 GT, assuming you wanted to do some gaming, I would go with the SP35P2.
no gaming would be done. Im thinking of low level C2D like E6300 or around there. The only reason for an 8800gt is that a friend works at nvidia and I can get a killer deal on one. I wouldnt mind using a 8600gt either.
I'd highly recommend either a passive 8500 or 8600 for no noise, or an 8500/8600 with an aftermarket cooler if you're worried about temps, but still want to keep your card cool. An 8800GT would just create lots of noise and heat, especially if all you're doing is video playback.
Are you getting a deal on those Ballistix also? Otherwise, I'd recommend something cheaper if you can find it. No point in using Ballistix unless you're going to overclock a lot.