Yeah with the release of the new ati cards so soon, this is probably a good time to wait and see what happens in that front.
The megalehems is definitely one of the best heatsinks, but your certainly paying for the privilege. A cogage true spirit has been reviewed to have similar performance with a much easier to swallow price point.
It may be the best heatsink available when paired with a good fan. You are talking about only a couple degrees difference compared to other quality coolers like the Hyper 212 or Xigmatek Dark Knight that cost half as much. 3.6 should be a trivial overclock for the i7 920 on any of these coolers. You should can realistically try for nearer (possibly even over) 4GHz.
Here's a build that will get you that 3.6GHz, run cool, and includes dual HD's. Also this leaves you money to pick up another one of those vid cards for SLI. Take a few min. and o/c this card yourself if you feel the need.
I wouldn't even dream of building a rig this expensive and not including a SSD considering how much faster everything in your system performs with one. I also echo what others have said about waiting for the new video cards. I wouldn't even bother with SLI with one of those since there really isn't anything you couldn't run with just one of them. And there's always room for another card down the road if needed.
The ASRock motherboard did get good reviews, but as much "for the price" as just being a good motherboard. If budget allows, the EVGA in the OP does look to me like a better board and EVGA has a good track record.