All good items picked out there. I might make a couple changes then onto the MB.
I personally prefer the WD Black drive. Same price and size, two more yrs of warranty.
Western Digital Caviar Black WD7501AALS 750GB 7200 RPM SATA 3.0Gb/s 3.5" Hard Drive -Bare Drive
Love your RAM choice, likely the best stuff out there right now.
GPU - looks like popular and recommending gaming choice - not my area, I use the built-in on my MB!!! But see below re motherboard.
PSU - Don't know the brand, looks very nice and enough connectors to run a battleship. Might find something good quality for less. Doesn't say 2 rails, make sure of that!
Now, your GPU is CrossfireX and you've chosen a motherboard that doesn't support Crossfire at all. This would seem to be a mistake because it dooms you from further enhancement of your GPU performance. And if I'm not mistaken, lack of Crossfire support on the MB reduces the performance of a GPU even without a 2nd GPU.
Most folks here don't think much of MSI boards, you'll see that in comments in other threads and likely in this one soon! We tend to recommend Gigabyte and Asus because of personal experience, quality and performance. Doesn't mean MSI isn't a good board, just not often a favorite.
Here's my suggestion. Below I've listed the homepages of Gigabyte and Asus. Choose the 1156 socket - which gives you P55 boards - at each location and browse what they have. Below that is the same Asus and Giga and also MSI boards avail at NewEgg.
Look for the features you liked on the MSI board, but include CrossfireX in your items. You can't always trust the short blurb of features at NewEgg and don't make any choices directly from NewEgg w/o checking the specs at the mfg site. In addition, when you've narrowed down the choice, read the manual for the board front to back!
Gigabyte
http://www.gigabyte-usa.com/Products/Motherboard/Products_List.aspx?VenderType=Intel&CPUType=socket+1156
Asus
http://usa.asus.com/ProductGroup2.aspx?PG_ID=mKyCKlQ4oSEtSu5m
Newegg with Asus, Giga and MSI
http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=2010200280%2050001315%201070549182&bop=And&ActiveSearchResult=True&Order=PRICE
http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=2010200280%2050001314%201070549182&bop=And&ActiveSearchResult=True&Order=PRICE
http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=2010200280%2050001312%201070549182&name=LGA%201156
Good Luck!