For reference, I have an i7 920, a single gtx 285, and ram at ~1680Mhz with 9-9-9-24-1T timings. The i7 is oc'd running at 4.1ghz 24/7 with air cooling. If you're getting a liquid cooling system you'll have no probs running it stable even higher.
And with those parts I can run Crysis/Crysis Warhead completely maxed out at 1920x1080. That's with AA enabled as well. No lag at all.
Really, go with the 920. The 975 just isn't worth it when you can get similar performance from the 920 for FAR less. And two gtx 285 SLI'd together will be fine. In fact, it'll be much more than just fine, it'll be completely amazing.
And just so you know, Slay was kidding about that ram set. Get these, or two of these if you must
Newegg.com - G.SKILL Perfect Storm 6GB (3 x 2GB) 240-Pin DDR3 SDRAM DDR3 2000 (PC3 16000) Desktop Memory Model F3-16000CL7T-6GBPS - Desktop Memory
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