I don't know what their BIOS looks like, or what kind of things you can tweak with it, but DDR2 is still perfectly acceptable to me! I'm running it, and been driving my girlfriend nuts with how much time I spend messin with it! Here's some specs for mine.
AMD Phenom 9850 AM2+ OC'd @ 2.9GHz HT 3.0 5200 MT/s
8GB Crucial Ballistix DDR2 800 MHz stock running overclocked to processor 930+ MHz @2.05V 4+4+4+12 timings
ATI radeon HD 4870 512MB GDDR5
MSI K9A2 Platinum overvolted & overclocked chipset
Antec 850W PSU
Windows 7 x64
It was a fast machine 1 year ago, and it still is pretty fast, but it doesn't have it's own thoughts like it used to. CPU's GPU's and RAM is 2x as fast as they used to be.
However, I've been doing a lot of research on RAM speeds and latency timings and such. Turns out, DDR3 timings are fairly loose as compared to the max that DDR2 had. I think before I upgrade to the Phenom2 965, I'll wait to see what the timings for DDR3 get to. You can still build quite a machine with the MoBo you've got, and O/C will help. If you've got a phenom, you can still go up to at least 2.6 GHz (depending on which one you've got, maybe higher) and DDR2 is still really fast. If you O/C and overvolt it, it can still perform as good (maybe even better) than DDR3 with it's current latency bottleneck.
The big item I'm waiting for is the XFX 5870! DX11 and that card will burn the cases of PCs everywhere! WHOOO!!!
All RAM is pretty much the same, as far as brand is concerned. Just look for lower latencies, and go with 1066 if your board supports it, and 800 if not. It's fine, and you can still O/C it. I got a screeny of FSX running a spike up to 209 FPS, and I'm quite happy with it. Hope this helps you out. If you've already finished your build, what did you decide on?
Asus Crosshair V Formula-Z
AMD 8350 @4.65 GHz on H100i (226.8 x 20.5)
8 GB DDR3 1814 MHz CL8
ATI 6870 HD Radeon 1 GB
Antec 850 W PSU
Cooler Master HAF 932
500 GB and 200 GB HDDs
Windows 7x64
VRS F/A-18E Superbug, PMDG 747-400 & -8 and MD-11, Captainsim 777, Iris F-14A&B and A-10, Area 51 C-5M Super Galaxy and C-17, loads of others.