I am not a huge fan of AMD, so I don't keep up too much on their products. However, I believe due to the way they design their CPUs these days, they do not yet support DDR2. If AMD is truly this important to you, go with DDR1. DDR1 vs DDR2 isn't yet that big a difference, and DDR1 is on the AMD roadmap well into 2008 from what I hear. I guess it's something with DDR2 having higher latancy because of some such-n-such detail.
If you are truly starved for DDR2, I suggest going Intel. They have some excellent DDR2 offerings, and infact I own one of them. I have a mobo based on the 845G chipset, and I couldn't be happier. I do have to point out though, if you want something as close as possible to what you describe, changing your processor is a much bigger difference than ram type. Just like when DDR1 was first made, DDR2 isn't a big difference right now, and isn't necessarily "needed".