Yes, a X2 3600+ is still a great CPU; I got my 4200+ 1 month ago; my board allows me only a miserable 2.45GHz but that's still lot of performance, and in a while, you should be able to upgrade to K10 CPUs, probably kicking even the actual Core2s :wink:
It's highly debatable. Even if K10 has 40% more performance than QX6700, Intel might still be a better buy for overclockers since it will have superior production techniques
Of course, but don't forget that AMD is trying to catch up Intel in process and they had to rush a not yet 100% stable process, which can mature 5-6 months later with the new releases. All this said, Intel will still have IMO the better lithography, so AMD HAS TO puull at least another 400-500MHz if they want to be well in the game.