Go the dual core Athlon X2 4800+, or the dual core Athlon X2 4400+ (if you wanna save a bit of cash). These CPU's kick the hell out of Intel's single and dual CPU's.
I disagree. Anything Intel is better for video than AMD. This is because Intel handles data throughput much better than AMD. AMDs are much better suited for gaming than video/graphics. Also, the Intel's are much cheaper than the AMDs.
I find that EE Intel's w/ HT are best for video editing. However, Dual Core is definitely the wave of the future so make sure your mobo supports it. It is said that dual core allows you to run other programs, check your e-mail, surf, run other apps, etc. while rendering video to output, but I would never trust it, personally. You just don't want to freeze up during that time after all of your effort.