If you go for 470 sli yes + that 8800, you will probably need such a power supply.
If you plan on going this way, you'll need a 1366 socket with an i7 9xx.
I'd recommand you the 920 since you can get an after market cooler and the cpu for less than the 960 which is 400$ more than the 920.
So, get the i7 920+a good 1366 motherboard, 3x2 ddr3 modules. 1600-2000mhz, a good after market cooler, a good case, the 2 gtx 470 and the 1k powersupply.