[Alfred Williams]

the 4850 will beat it hands down. usually with HD editing you want to have the most you can get( Video Memory) cause Hd takes up a lot(Video Memory)
all i do is hd editing and i have a card with 1 gig of Vram. of course its not just that, you also want to make sure your card is fast. if its just editing then its not a big problem since only a very few editing programs take use of the graphics cards full capabilities. i know both the gt 130 and the 4870 come with 512mb but i would still choose the 4850 since its faster, not that your editing software will use its speed but its a safe bet for the future. since Adobe just came out with Premiere pro cs4, which use more of the graphics then before im sure all the other high end companies are to follow in the same steps.

hope that helps.