I dont see any reason to go above DDR2 800. With a Q6600 @ 400 x 9 you will hit 3.6GHz and you RAM will be link'd and sync'd. Since you have a SLI capable board I would say go with SLI Ready RAM. I have had some bad luck with SLI Ready RAM but I am hoping it was just a couple bad sticks or 1 bad stick and a brown out / power spike that fried the RAM the second time.
The EPP timings and ability to OC has been good to me so far OCZ SLI ready 2x2GB. I got this stuff running @ 850MHZ with out even thinking about it. I am sure it could go higher.
Why not go for RAM that's rated to run 1066 out of the box? With the price of DDR2 nowadays it doesn't really matter. That being said, any DDR2 800 worth it's salt should do 1066 no problem anyway. And I ALWAYS got better overclocks, and more options by unlinking the RAM on my 680i. The same went for my 780i for the short time I had it.
And SLI Ready memory. What the hell does that even mean?
I'll bet a dime to a dollar that if you told any experienced RAM Overclocker that you were going to buy SLI ready memory because it's going to perform better with your SLI board they wouldn't be too quick to agree. In fact they will probably tell you what I'm going to tell you; Read the reviews, see what the benching teams are using, find a good deal and overclock the hell out of it. Forget the gimmicks.
I am also considering some Patriots. Is there a difference here other than color?
And UBERCOOL, as far as I know, the color difference is due a new lineup of memory, most likely corresponding to the release of the DDR3 Vipers. I haven't been able to find any difference between the two, but then, I haven't really researched it that hard.
Google it, all the info is there.
I like! They took a long time to get down to a decent price though.