Re: AM2 vs. 939
Am2 vs S939,
Well not too much difference except that AM2 uses ddr2 memory, which doesn't make that big a difference where you will notice a difference from ddr400 memory. The Am2 has the built on memory controller, which does make it better, but there is a lot of discussion that it makes the memory run slower or faster. I haven't found any websites that crush that rumor so its pretty much up to you on that. The AM2 is great because if you want to use a sempron or go to the 5200 you can on one mobo, which i like over the 939.
I'm on S939 (specs below) and i have no desire to go up to the AM2 because i wouldn't see any difference between the two.
If you have the money go with the Conroe set up because it is cheaper and beats the daylights out of AMD. So 6400 for major OCing or 6600 for 4megs of shared L2 cache.
That should clear up your questions hopefully.
3800x AMD, ASUS-E mobo, four 512 sticks of ddr400 (duel channels), Nvidia 7900gt OC, 80gig, 120gig, 200gig, 320gig, 400gig WDs, and a Soprano case