This should be in the system section but you don't need an i7 for gaming or 16gb of ram. Just get an i5 3570k and 8gb(2x4gb) of corsair vengeance lp 1600mhz. Also you could get a much cheaper mobo that's very good asus p8z77-v lk or if you have to get a better one this asus p8z77-v. Now if you plan to get a second gpu later for sli setup then get the 750w psu but if you don't plan to just get a 550w psu like the xfx pro550.
The 3770k actually beats the 3570k by quite a bit in a lot of the highly threaded games like BF3. If he isn't sacrificing anything anywhere else and he has the money to waste anyway, then let him get the 3770k.
If he branches off into audio/video editing he would be glad to have the 3770k and the 16 GBs of RAM.
It isn't that uncommon for gamers to want to record videos, edit them, and throw them up on youtube to show their friends and so on.
With that money I said he could save earlier, I would go up to a 256 GB SSD if he still wants to invest it.
It's based on LGA 2011 which is Intel's high end platform.It has 2.5 times the PCI-E lanes of LGA 2011 making it very suitable for a multi-GPU gaming system.It also has a upgrade path to the upcoming Ivy Bridge-E so if you need a better processor in the future you wouldn't need to buy a new motherboard as well.
It has quad channel 16GB RAM which may or may not be usefull for you.
It uses a Sapphire HD 7970 GHZ Edition which is more powerfull than a GTX 670 overall *yes even the FTW.It's cooler is also very silent and it's a very good overclocker.
It has one of the best cases on the market.
And it's monitor is a huge improvement over the one you listed.
Why prepare for multiple video cards when the OP hasn't even expressed an interest in it?
Not to mention x16 / x16 actually benchmarks lower than x8 / x8 does most of the time due to the added overhead broadcasting from the NF200.
If he did express an interest in multiple video cards, its likely people would just talk him out of it anyway, I know I would give it a shot.
The XFX 850w would also be overkill even for 2x 7970s.
Not sure what you read about 7970 OCing, but what I read says they don't benefit much from OCing.
While max FPS can be pushed 20% higher, that translates into more like 5% for average FPS, and an actual loss on minimum FPS (the most important sort). It is certainly not worth pouring 20% more power into it to get those results.