HyperX PC3700 or PC4000 with NF7-S board?

I am buying a new board and memory to match up to my 2800 Barton and 9500 Pro. The board is an NF7-S and the memory is either Kingston HyperX matched 256x2 pair of either PC3700 466 mhz or the new PC4000 500 mhz....Will there be any advantages with these speeds of ram on this board or should I save a few bucks and go with HyperX 433 mhz?

HELP! I think I'm going crazy with all this madness!
(Thinking I am really addicted and need counseling)