Like pjz99, I built my machine 10 months ago and the only quad available was the QX6700. But
if I were going to built today, I'd go for the QX9650. Only because it's a 45nm architecture chip,
and the extreme chips are unlocked (better for overclocking). Now if money was an issue, I'd
wait for the regular quads to come out with the 45nm, these 65nm chips run hot, way HOT.  But
all in all, I'm very happy with what I have now. Haven't been able to bring it to it's knees yet. And I
love loading up scenes. 8-)