First Build Recommendations

If you're getting a K series CPU, it's only worth it if you're interested in overclocking (which requires an aftermarket CPU cooler as well) so you'll need to factor that in. The Hyper 212 Evo is a great budget one, that won't set you back to much.

You could go for a non-overclocking build, and purchase a 3470/3350P instead, since the stock performance will be very, very similar. This should save you like $50 on the CPU, but if you want to CrossFire, unfortunately you can't also pick out a cheaper motherboard, because you need a Z77 to support CrossFire.

One area you can save in ins the SSD. You won't notice any difference between that very high end one, and something like the 128gb Sandisk Extreme, even though the latter is $50 or so less. The longevity will also be the same since they both you MLC NAND, and the speed will be similar enough that for your usage, you won't notice the difference.

Another idea is to slightly change up the power supply. Unless electricity is particularly expensive in your area, a Bronze 80+ will be just as good as a Gold 80+ (note: there is no implied difference in quality between a Bronze/Gold power supply, only efficiency). A Corsair TX750 saves you about $30, but obviously its a tradeoff for features such as modularity (I have used both fully modular and non modular power supplies, and there is no real difference in my experience unless you want to custom sleeve your cables) and Gold efficiency. Here's the power supply mentioned: http://pcpartpicker.com/part/corsair-power-supply-cmpsu750txv2

The thing is I don't really see any point in you buying quite a few features (CrossFire, overclockability) that you don't currently need. The nature of technology is such that stuff becomes cheaper at an exponentially fast rate, so buying stuff that you don't need now, but might need in the future is silly, since we can be sure that the same stuff will be much cheaper by the time we imagine we'll need it. For example you could drop to a 500W power supply, a H77 motherboard and an i5-3470, and have exactly the same current performance, for the price you're asking. What would you lose out on in the future? You might say the ability to add another 7950, but in 3 years or so time, do you really think you'll want to put another noisy, power hungry, hot and 3 year old graphics card in your system, when there's a 9870 or whatever which performs better than CrossFire 7950s for less than the current price of a single one? Yes, 7950s will likely be cheaper by then, but also end of life (so not guarentee, you can't return them if they break) and you have to factor in the added current cost (bigger power supply, more expensive motherboard) of having the option to add one.

Anyway it's just some food for thought.

EDIT: lol at how Ksham makes very similar suggestions to mine as I wrote this great wall of text out. Oh well, great minds etc, etc (and now it's a doubly good suggestion). I wouldn't go with the Samsung 840 non-Pro though. The Samsung 830 series is actually better for the same price, since it's the predecessor to the 840 Pro, rather than the just stock 840. Samsung really skimped on their standard 840 I feel, using TLC NAND rather than MLC, which is both slower and has half the write cycles of MLC (5000 for TLC vs 10000 for MLC).

M