Stability > Extreme Frequency pushing. You are going to be overclocking, so look at RAM that can reach 2000MHz without pushing it too far. Kingston HyperX T1, Mushkin Blackline, OCZ Platinum, Corsair Dominator GT and RAMs as such are fine. I'd rather not go with the 1600MHz kit you mentioned, as pushing RAM 25% over it's maximum rated speed isn't good for temperatures and stability. And with your CPU running at 4.2GHz (respect), you want stable RAM!
The 1600mhz kit is what I have now lol. It is set to 1600mhz which is as low as I can set it in Bios because of my CPU overclock. I even managed to tighten the timings to 6-8-6-20-1T on 1.65V.
Edit: Actually DRAM Frequency can be set to 1200, 1600, 2000 with all my other settings untouched.
So what is so special about this memory that warrants $215? The specs are a little worse than what I picked out. The only plus I see is the RAM fans don't have blue LEDs that I am going to have to mod to red or disable.
I'm not really a fan of the Corsair Dominator series of RAM kits, just because of it's immense pricetag. I'm also not really familiar with it, because of it's pricetag, people tend to avoid it. It also isn't too good looking (I'm not a fan of the red colours, I like black/blue schemes). If I'm to choose high-speed RAM, I'd probably go with something like OCZ Reaper, OCZ Platinum, Kingston HyperX T1, Kingston HyperX H2O (watercooling heat spreader fitted as standard), Transcend AxeRam 2400MHz (currently the fastest RAM on the market I think?) or something like that.
I don't know how I didn't notice the memory I was looking at was 4GB (2gbx2) and not 8GB lol.
I looked at you recommendations and first I can't stand Gold / Silver OCZ so that was out and the others I could not find good review / 8gb (2x4) / DDR3 2000. The only memory I could find that has what I need and my mobo is even on the QVL is this...
I've NEVER worked with G.Skill before, that's why I didn't recommend them. I've heard good things from them though, so there's no reason to not try it.
The reason you wouldn't find reviews for the 8GB kits is because very few people actually use 8GB kits. 4GB is more than enough for any game out there today, so reviewing 8GB kits is a bit useless. In the future they will get reviewed though, mark my words.
I'd give a +1 for matching the 1600MHz with the 1600MHz you already have, just make sure that you do your channeling correctly with the old set. New chips in the one colour slots, old chips in the other colour slots. That way you will correctly use the channels and not end up running all that RAM at slower speeds.
Personally i have that Gskills kit and it's very good.
For the price it's hard not to recommend buying another kit.
More or less half price from what they cost last year at this time($120).
Imo the 2000Mhz kit isn't worth it and fan coolers are a gimmick imo.
Btw Toxxyc OZC has a terrible reputation for DRAM which explains why they are out of the ram business as of 2011.