I need to build a fast encoding and capture machine.

We encode lots of mpeg and Windows Media with Cleaner. We also need to capture real-time mpeg and WMV.

Any suggestions on what kind of card I should get? And as far as price/benefit on processors, should I go for an Athalon XP or P4?

I have an AIW 7500 at home, and am happy with the real-time mpeg capture, but it doesn't do so great on Windows Media (lots of dropped frames.)