HD and HTPC Configuration Advice Needed

Greetings All...

I am interested in building a new HD home theater PC, strictly for the purposes of watching movies and sharing media across my personal home (while connected to my plasma via hdmi of course).

I have the network infrastructure part completed hardwired and wifi (since that's what I do for a living), but am a little stumped when it comes to determining the selection of a motherboard and graphics card,etc.

In 2008 I built a HTPC using an ATI AIW video card and was able to simutaneously watch TV and use my computer. Is this still a possibility?

If possible/practical, I'm thinking about reusing a mid-tower ATX case that is in nice shape, as well as my Zalman ZM600, which has seen very little action.

Anyone care to share some insights on what they would buy for a DVD drive, motherboard, and graphics card?