sensible system specs for MC5

I'm upgrading to MC5 for Hi-Def work, particularly AVC/h.264 transcodes from Canon 7D footage.
Gotta get a new 'puter. Don't wanna spend $3k.

I'm wondering what's an acceptable spec. (not annoyingly slow, but not necessary a speed freak).

If you're using MC5 for Hi-Def could you do me the favor of responding with your CPU and memory specs, and whether or not you're happy with your system. What would you improve?

I understand that this is all subjective and work-flow dependent. I'm just a blind man trying to get a feel for the elephant.

thanks, Craig Umanoff
Moving Pictures
Portland, Or.