MOBO:
The Mobo you have mentioned has a AMD 970 chipset, the latest amd chipset is 990 / 990FX (AFAIK) since you want the build to be future proof i would recommend you to get a 990 based chipset. Get Asus M5A99FX Pro2.0 its a nice board, Also get asus or Asrock brand mobo.
You got a nice gpu, but the mobo is a bad or poor choice when it comes to sli a high end card. chk this
http://www.tomshardware.com/answers/id-1633531/msi-970a-g46-sli-crossfire-support.html
If you are budget, get M5A97 but if you are planning to sli / crossfire get a board with 990/990fx chipset.
970 chipset boards don't support sli/crossfire. The second card may not be running in its full potential or bottleneck when SLI or Crossfired.
CPU:
6300 is a good choice if you are on budget. if money is not a constrain get a FX 8350/8320 ->8 core cpu.
RAM:
Get atleast 4gb 1600/1866 Mhz ram with a CAS latency 9. 8gb should suffice unless your priority is heavy video editing or memory intense applications. Corsair vengeance (Red) or G.Skill Ripjaws
Get 7200rpm HDD. Also if you want your apps n os to load much faster get a SSD they are bit costly but worth every penny spent on it they also get longer lifetime compared to hdd.
750 watts should be good. but i am not sure it may be a little bit of overkill (ruling out overclocking). If you are overclocking even a 750 watts wont suffice along with SLI.
ON SHORT:
Get a 990 or 990fx based mobo. Gpu is a good choice
Get FX 8 core if you are not on budget.
Get 1600/1866 Mhz RAM with CAS 9
Get a Branded PSU like Corsir TX series or Seasonic
Good Luck on your build
Hope This Helps you...