I'm using DDR on my A7V266-E with an AthlonXP 1500+@1700MHz. Now I might be talking out my rear end, but I think Intel is starting to steer away from Rambus memory and going with DDR. Someone correct me if I'm wrong, but I think that is something I read (can't remember where). Could have something to do with the cost of making Rambus memory chips.
Anyways, just check your mobo manual and see if it supports DDR and go with that if money is tight. If money is no problem, get the RAMBUS due to its better performance over DDR!
GearJammer
qlm tera'ngan!
(Translated from Klingon: Attention Earther!)