The final choice is always yours, but if you ask me, and if you're interested in a 4 core CPU, i would go for the AMD X4 9850 Black Edition, in the same price range of the Q6600 (the difference is less than 10€, at least here) and slightly better. Unless you're a Intel fanboy, which is perfectly normal and comprehensible at the moment: Right now, the X4 9850 seems to be the only AMD serious threat to Intel's market dominance.
The rest of your computer looks good. The monitor could be a different one (Samsung and LG are brands that, in general, deserve a look about it) but that Acer handles the job no problem.