Personally I think the ASRock Extreme4 GEN3 is by far one of the best boards out there at the moment in terms of features, price and performance.
I helped a friend build on one last night and it was very impressive. The spacing between CPU and RAM was great, the connections were all where you would expect them to be, you get front panel USB 3.0 support along with firewire as well (obviously depends on your case though). The board was very high quality and the black and gold colour scheme was beautiful It comes highly recommended, and from personal experience too!
I must say that ASrock boards are very popular now. The one you have chosen has great features and good reviews. But, you really cant go wrong with ASUS either. Both boards will have support for IvyBridge as well.
Seems like you could probably step down to the Gen 3 though, as neonneophyte has suggested.
You don't mention a case and I'd be wary of a new 2500k build and a 6950 GPU with only a 500W PSU.
I just got an ASRock Ex3 Gen3 and it looks good so far, only had it a few days though. It does allow SLI or Xfire and has UEFI BIOS and lots of fan headers.
I put a CM Hyper 212+ on a 2500K facing upward and it still clears the GSkilll heat spreaders on the 2X4Gb CL9 in the first RAM slot in an Antec 300 case.
Case has a bottom mounted PSU though so SLI would be tough with a double wide GPU.