One note on the DDR2 questions. If you look at what overclockers have already done with DDR2, you will see that there is room to get latency's down and really improve its performance.
D9 chips have been the most popular in DDR2 overclocking. I know for sure Fugger hit DDR2-800 with D9's at 3-3-3-15. I am not sure what the world record is.
Point is, the potential is there, and I think that now that AMD is in the DDR2 game, it will further push chip makers to put out some good low latency DDR2-800 sticks.
Mark my words!