My 2 cents would be get that setup listed in the second picture with the 670. You would not have to think about another video card for a long time, a 570 or 560ti would keep you happy for now, but the future might be somewhat lacking.
Your motherboard seems to be a strong choice, good room between 2 card in potential sli, pci-e 3.0 (even though 2.0 is not saturated by even 690's so no need for it) and plenty of room to oc cpu+ram
100% go with nvidia, dont choose anything from ati, its long and complex story but to summerize it, nvidia has much better driver support, you will never be left waiting for "drivers" to come out for a new game
I would say that the i5 2500k will provide you plenty of power. Yes the i7 is slightly faster, but you will never notice the extra money spent when it comes to gaming performance. If it were up to me, i would get the i5 and overclock it, and put the money i saved on the cpu into a 680, you will notice that extra money much more than spending it on the i7.
Your psu isnt horrible, but isnt great really either, to me a psu you dont want to buy a bunch, and can easily be transfered from this build, to a future build so there is no reason to got go for a 1000w psu just to be sli safe in the future, but also ensure that you will have enough power for furture cpu's also, i would suggest something like this for your psu....
LINK...i will likely be tared and feathered for suggesting rosewell, but it has good amps per rail, and enough watts to keep you happy with just about sli anything and possibly tri-sli depending on card choice
I would go simple with the heatsink for now, the Scythe Mugen II is a great choice, only beat out by a few other coolers, and even then its by 3c at most usually. Link provided
HEREi havent read up on the mugen 3 so i can not comment as to how it performs, but again the mugen 2 is a solid choice
In hopes to stop any potential criticism, yes cpu is important for games, but an i5 2500k would not even bottleneck 680's in sli, so from a gaming stand point un-needed horsepower...
That