Congrats man. I did the exact same upgrade just 3 weeks ago. Q6600 to 2500K + 8 GB and I'm very happy too, like night and day in games and rendering. My election was a lot easier though, because in the retailer where I get my parts from, the 2500k costed exactly the same as the non-k 2500 (~180 euro) and 80 euros less than what the 2600k costed. 50% higher price for so little improvement could not be justified, even if the 2600k itself demolished any Westmere i5/i7 CPU in price/performance. The ram was an even easier choice since they had a 2x4GB Patriot 1600 Mhz bundle for sale for only 5 euro more than 2x2 GB bundles and I do have a use for so many ram, so... It's funny but I've seen dozens of people going from Q6600 to 2500k, I don't know if it's because both are/were such a good deal (which they are) or it's just that seing Q6600 and 2500k together calls my attention.