If you plan to SLI get a PSU of 700+ watts now and save on upgrading it later. 16 GB of ram isn't really needed for gaming, 8G is more then you need, but is see you are just trien to fill the 4 channels. If you do want to get crazy ram, it is up to you if you want to go for more ram or faster ram, as their are some crazy fast 2g x4 kits out there.
Personally I would get the K version of that CPU and use the 500$ you save to upgrade your GPOU get a GTX 580 or better and you wouldn't even need to SLI for a long while. If you get the i7-2600K or i5-2500K, you would save even more.
Unless your using this for something specific other then gaming the CPU and RAM is way overboard.
Nvidia is lining up to release their new GPU series. If you're willing to wait another month (or two), you'd get the power of the GTX580 for half the price.
People will always tell you to get the GTX?80 card - that's because they're not paying for it. The performance per dollar on the ?80 is usually not worth it. It's there for those that compete for the best rigs but is usually not worth it.
I'd look at what you're willing to spend on a GPU and go with these recommendations for now (again, unless you're willing to wait another 1-2 months).
See that there are a bunch of cpu in the same tier as the one u posted. that means they have similar performance. You would be paying for more than two 2500k without gaining a significant boost when it comes to gaming.
I say get an LGA 1155 mobo and a 2500k and maybe a 7950. At least that's what I would do with that kind of money.