As I am planning a new PC build in the next few months, my plan is to turn my old PC (Dell XPS 430) into my Home Theatre PC. Since I've had the dell, one of the things I upgraded a little while back was the GPU. It currently has a Radeon HD 4650 installed. I've looked over some other HTPC builds and I saw a medium level build that used the GeForce GT 430. My future plans are to add a blu-ray drive and watch movies either via blu ray or download and I'm just trying to figure out the best setup for a minimal budget. The main question I have here is which GPU would be better for what I'm planning to do? I know very very little about GPU's so any help is appreciated. Thanks!
If you weren't planning on using the unit for anything beyond watching videos, then you don't need to do anything. Can't quite pin down with any certainty whether or not your specific video card supports hardware accelerated video decoding... It looks like the 4xxx series was where it was added, but it may have come just a little after the 4650, but it shouldn't matter. There should be ample CPU power to muscle through even high bitrate 1080p content with ease.
So, at most, just look for a cheap video card with hardware accelerated video decoding. Anything from the 5xxx series in the Radeon HD series should be a safe bet, and I think anything from the GeForce 2xx series on is also a pretty safe bet.