Gah! No stores in Florida!
If you're considering an SLI system, the motherboards are about the same price as the C2Q boards (790i SLI), you'll only be spending a little more on RAM (assuming you're looking for performance RAM, which you should be if you're going for top level stuff), and getting and extra stick/channel. I was torn between building a Core i7 system and saving some money by going with a C2Q, but when I looked at the motherboards (for C2Q) that had DDR3 and SLI support, my decision was made. They're all ~$300 for either platform, with some of the i7 boards dropping to $250.