Ripjaws Z or Trident X.
Stick with G.Skill, or if it's absolutely not available, Mushkin is good too.
AVOID: Corsair!
You want to find the HIGHEST SPEED with the LOWEST TIMINGS.... Examples:
2400 11-14-14-35 vs 2133 9-11-11
Second is the better choice
The above is especially relevant when the sets are from the same series of memory (i.e. Trident X 2400 9-11-11 vs 10-12-12), as the kit with the lowest timings will almost always have the best binned IC's, whereas the looser timings are kits often made from either significantly less capable IC's (think Nanya or anything Elpida has done for the last, well, while) OR they are the same IC's as the first kit but didn't manage to achieve the speed and timing combination required stably, so they're 2nd tier IC's.
Since the move to Hynix and Samsung as the big players in the RAM world, with IC's of old such as PSC/Hypers/BBSE/etc no longer available in anything but the most minute of quantities if at all, CRUCIAL and Kingston amongst others seem to have had a very hard time switching; quite frankly, while not bad, there are always better kits for the price.
And Corsair, the biggest sell-outs in the computer part world... Their Dominator kits are average yet cost 2-5x as much as kits from other companies THAT CONSISTENTLY OUT-BENCH THEM! The Vengeance series contains everything from quality CFR/HYK0/etc IC's to Nanya/etc, but probably 95%+ are the latter, you have zero idea what you have until you receive them, and it doesn't really matter anyway as they are binned so absurdly aggressively that you will be among a single-digit percentage if you can overclock the memory at all (and i'm not talking going from 1600 9-9-9 to 1866 10-12-11... timings must be equal or better relative to frequency or it's worthless and says nothing about the memory quality)...yet they're touted as a PREMIUM memory brand.
And XMS, which used to be THE ABSOLUTE BEST memory you could get, period, no questions... It's now a disgrace, with horrible performance as a result of corporate greed in cashing in on the names and hard built reputations of past products, by sticking the same name on a bargain budget (if that) kit of memory along with a $0.25 pair of heatspreaders and up-selling it for larger margins than anyone else, and destroying that previously well-earned reputation in the process...
Ugh, I don't like Corsair very much....