Very true, but OCing is only for some people....
I don't do it, and don't really have any interest in it....
At work I have two boxes which are QX6850 based with 1066 RAM etc. There is no way I would buy Q6600 and OC them for that, so not strictly a fair competition....
I'd be willing to bet a QX6850 will have better results for me (high-quality decoding, rendering etc.) and spend less time doing it than a clock for clock Q6600. Yes, it won't be a massive difference, but time is money and I want it done quickly!
Personally if I were going for an Intel home machine, I'd go for an E6850 over the Q6600