I gave up on AMD, they are not going to make a comeback , I wish I could say they are but theyre not. Piledriver will be only a small improvement over BD.
Sandy Bridge cores are too fast and sweet to pass up. As of now the Sandybridge Pentium G630 which retails at like $79 beats the the FX-4100, -6100, and -8120 and thats the low end Intel offering.
Heres the link to verify that.
http://www.tomshardware.com/reviews/gaming-cpu-review-overclock,3106-2.html
All current Amd cpu's should be sub $100 but AMD is just saving face. I have a Pentium G850 in my system waiting for the IvyBridge quads, and that pentium puts my old phenom 2 X4 to shame.