+1 @ cadder. I considered those same points when I chose my Q9450 last year. 3.2GHz was a simple OC, as much as I want for now. I chose Mushkin RAM, which will readily OC.
I've read that that Q8200 doesn't have comparable performance due to limited cache. It's the sort of CPU you might be initially happy to have, and then be pissed at yourself in a month or so that you went cheap. Get the Q9400.