Good video card for socket 939 amd 64 x2 atholon processor?

What would be a good video card for AMD 64 bit dual core athalon processor for regualr desktop like watching movies and editing home movies.|||Nvidia GeForce 7800, PCI-X, preferably with 512Mb of RAM. Very expensive, though.|||I am currently running 2 gforce 6800 ultras. I have sli which makes a little difference but not huge. Anyways, they do a great job.