I know less AMD history than Intel since I pretty much jumped ship after the TLP bug in the first X2 and X4 chips. I can say for sure be glad you skipped AM2 / AM2+. AM3 is a much better platform but the chips are lacking vs intel.
Intel wise, Netburst finally died after Pentium D and heralded in the Core micro architecture that has made intel the performance leader ever since. It started with the dual core E series, then the quad Q series both on a 1066 bus. Great chips. Tick. Then came the shrink to 45nm and the E/Q shrinks that boosted clocks as well as the bus to 1333. Tock. Next intel brought in Core 2 with the i3/i5/i7 which brought further clock for clock performance increases, the new QPI interface (replaces "FSB"), on-die memory controllers, as well as Turbo and the return of hyper threading. Tick. Then came a shrink to 32nm and the i3/5/7 got lower power consumption, higher clocks, and some new features. Tock. Finally we arrive today with the 32nm Sandy Bridge, also known as Core 2 v2 that has once again shaken things up. Cheap, low power, turbo, super performance and overclockability. Plus, for the first time ever, 2Ghz @ .8v while idle and 5Ghz @ 1.50v combine in the same setup thanks to new and improved on-chip power plaining and voltage offsets. Tick.