re: Building a computer for my brother (Updated 1/23/13)

I wouldn't buy the saber tooth. The only really attractive thing about it is the warranty. By the time u get close to making it worth while it will be time to move to a new socket. In other words I would only buy the saber tooth if u were gonna get a 2011 chip. I bought a 3570k with an as rock z77 extreme 4. It overclocks well enough and is pretty inexpensive. Ask around as others have bought asrocks and been pleased with them.
I have a gtx 670 and it runs everything on ultra. A 660ti would be fine too as would a 680.
I know you are buying a 850w psu so that he can sli if he needs to but I wouldn't spend that much. For instance I went to bestbuy and got a 850w thermal take semi modular psu for 90 dollars. Buy a decent one by all means but u really don't need to dump 170 into one unless you are most definitely needing super high efficiency, silence, or definitely going to water cool and sli.
If u want a well made case look into fractal, cooler master, or corsair. I love my fractal define r4 and u can buy it with a window.