DDR2 has higher bandwidth and lower voltage consumption than DDR. The trade off is in latency, although technology has advanced so much that the latency difference isn't that great.
As far as the FX-60 goes...avoid. You're paying $1,200 for a Athlon X2 4800+ with unlocked multipliers. That alone is DEFINATELY not worth the extra $400 you can save by getting the Athlon X2 4800+. I'm pretty disappointed with AMD's decisions on the FX-60...