If it is a board meant to be used for an MD, I recommend on board video. That way your heat is at a minimum, and therefore the box runs much more silently. As to the 8xxx series of Nvidia cards, you may need to update your video drivers, but that is in the wiki, and all over the forums concerning the 8xxx cards. I have a 7xxx and a 6xxx series motherboard for my MD's. They are great for that, plug it into your TV, A/V receiver etc, and go.
The only regret I had about the boards I currently have deployed, is their lack of standard TV connections, i.e. composite or S-Video, or component, or HDMI. I use a VGA to (whatever you want) box on my MD's, which is an additional thing you have to get turned on for it to work, they are IR controlled, and therefore LMCE controlled, but its an extra piece.
The new motherboard I just ordered has HDMI, and composite as well as digital optical output. So it is ready to go, look for these features when you buy.
If they do not have it, then I can see using a pci-e card that would have say an S-Video output, etc.