If you don't intend to overclock there's really no point in buying faster memory unless you want to lower the multi and raise the FSB, and even then AMD64s have enough memory bandwidth anyways with LDT.
Despite popular belief, it is the CPU which dictates memory speed, not the motherboard. A motherboard supporting DDR will support any DDR speed, however the CPU FSB has to be able to support than speed.
On Athlon 64s, the memory controller runs the RAM at 200MHz, therefore you want PC3200 as you mentioned you were looking at.
Intel C2D E6320 / AMD Athlon X2 3800+
Gigabyte 965P DS3 / DFI nF4 Ultra-D
2GB OCZ Gold PC2-6400 / 2GB OCZ Gold PC4000
eVGA 8800GTS 320MB / eVGA 6800GS 256MB
150GB Raptor / 74GB Raptor
2x500GB / 320GB
OCZ GameXStreme 850w / OCZ StealthXStream 600w