Accepting that 2000mhz fsb/500mhz cpu ref is the maximum that board owners are going to use,where does 1066mhz memory come in to it?

The realistic available multipliers at 500mhz cpu ref are 2:00 or 2:40 B.
that equates to 1000mhz or 1200mhz memory speed.

Ive seen people dropping their cpu ref to get their memory running at say 1100mhz,but I havent seen any indication this improves pc performance.
Memory bandwidth/latency is limited not just by the memory itself but by the chipset.

Gskill trident 9600 memory (1200 mhz) memory for example would cover you for a lot of setups but they arent giving it away.Its at a price now where buying it would just help u decide to go for ddr3 and x55 or x58 boards,

It seems to me for overclockers that 6400(800mhz) or maybe 8000(1000 mhz) ddr2 memory has no disadvantages over 8500 memory,considering bandwidth limitations ,the multipliers available to us and cost.

If you dont overclock the cpu or cant get over the early 400's for cpu ref frequency its different.