I was wondering, what is the real-life difference between a single and a dual processor system? I mean, I know some programs are optimized for it, but how about things that are not? For example, which would be faster, the now-one-generation-old 867DP or the new single 1Gig? I'm still shopping around for my first mac, and wanted clairification on this point. I'll be using FCP3 which I know is optimized, but how much of a speed difference is really seen?