I would just go with some Xigmatek fans. Anyway, if you already have a i7-920, I think you would be better off overclocking that and getting two faster GPUs (like 6970s) and a fast SSD instead, but, whatever.
SSD is half as fast as today's current models. I'd hold off until ya can include a Vertex 3
GFX - Don't see the attraction of twin 6870's
Guru3D uses the following games in their test suite, COD-MW, Bad Company 2, Dirt 2, Far Cry 2, Metro 2033, Dawn of Discovery, Crysis Warhead. Total fps (summing fps in each game @ 1920 x 1200) for the various options in parenthesis (single card / SL or CF) are tabulated below along with their cost in dollars per frame single card - CF or SLI:
Last week that 560 Ti was $215 after MIR .... maybe it drop again soon. It will cost ya an extra $70 at today's price, but the change above save ya $101 .... net cost for an extra 161 fps is 31 dollars lower than ya original build.....and that doesn't include the 4 case fans ya needed. At $12 each that $48 + $31 + the $124 for the Adata SSD gives you $203 towards a Vertex 3 ($300)
From a cpu point of view, the 2500K will be much faster, particularly with a modest OC. It will do 4.0-4.5 easy, and will be 15% faster, clock for clock to boot. The 2600K will OC to the same levels, and I don't think the extra cache translates into that much more performance.
For gaming, spend your money on a great graphics configuration. If a single gpu will do the job, I like that better.
At 1080P, A single GTX580 will be as good as it gets. Just my bent, Having used both, I like Nvidia better.
I suggest a single GTX580, and see how you do. You then have an upgrade path. I would go with EVGA and use their 90 day trade in program is you think you might ever want a GTX590 instead of a second GTX580.
I think I'm going balls out on the rev.b with the 3000 rpm push and pull fans I'm going for 5ghz, I'm adding 5 thunderblade 120mm 2500 rpm fans for the case cooling. I have an xclio windtunnel from my last i7 build. http://www.newegg.com/Product/Product.aspx?Item=N82E168...
I want the nzxt because I have used it to build 5 custom computer for customers what do you guy think. The windtunnel is big and heavy and is not easy to move around