I would get this for the GPU:
http://www.newegg.com/Product/Product.aspx?Item=N82E16814121425
Same price, faster core clock and two fans.
Might as well get the i5-2500K for the few extra bucks, Z68 can overclock it. People here advised me to get the K version, as well.
The ssd looks like it has slow sustained sequential write compared to others, but the M4 had a firmware update last month to increase speeds.
Anandtech has a buyer's guide for each price range and has chosen the best, in their opinion, in each range. That might help.
You could probably go for a bit slower ram to get 8GB for the same price, up to you.
PSU seems like overkill. 750W is a lot.