I got lucky with the Ballsitix I got because they are rated for DDR1000 at 2.0v. And will run that speed on 1.8.v. Although I have never tesed for stability at 1.8v. Shortly after I got mine I noticed that everyone had changed thier specs to 2.2v. I assume they were running out of the better chips and/or were saving them for the higher priced modules. I pulled one heatspreader (HIGHLY NOT RECOMMENDED) and saw I got some GMH chips, nothing special. Good... but not special like the GKX or whatever the best ones are.
Anyways, There is no refuting that DDR3 has more bandwidth. But, they just are not FASTER. So relatively speaking, unless you need more them 6.4GB/s running back and forth, your not really going to see squat for difference.
look at the previous articles bench results here:
http://www.tomshardware.com/2008/01/04/ddr3-1333_speed_and_latency_shootout/page23.html
This is the important one for the vast majority of us...GAMERS!
Every module from top to bottom, from DDR1066 to DDR1600. There is only about a 5fps difference from highest to lowest. About a 2% variance. I bet if you toss in a few DDR2's at 1066, they woould score about the same. So if you can afford close to $300 and like throwing good money after bad then be my guest. Also if you just want to be able to say you have DDR3 thats fine too.
I just dont like people who "recommend" things without explaining why. All DDR3 actually does is add +1 to your e-penis, and take away all your beer and hooker money. No need for any DDR3 available today. I would admit that I think the latest chipsets are definately getting better than my P965 but we are still talking about very marginal gains after all.