Thanks, Trevor, this gives me a place to start.

The reason why I wanted to get a faster machine is to both capture video and process it. I did buy a Firewire card for my primary machine (P3 750 laptop with a docking station that accepts PCI cards) and that setup did not work well. I could capture about 30 seconds of video and then the machine would freeze, forcing me to kill the task. I suspect it is mostly because I'm capturing on a laptop through the docking station and writing out to a slow drive.

Eventually I would like to burn DVDs and I was under the impression that it took a fast machine (P4 or so) to burn DVDs effectively.