Re: suggestions to build...
You don't need a quad core for gaming, save a heap of money and downgrade to an AMD Athlon II X3 445 or something, and purchase a motherboard with a core unlocker, unlock to 4 cores, OC to 3.5GHz. I have, so I am effectively running a processor worth a lot more money than what I paid.
Most games only use two cores on your processor, very very few use 3 and games using 4 cores are almost non-existant.
You can also OC that GPU you chose to a 470.
Puchase a Western Digital Caviar Black/Blue/Green HDD. They are good, black would be best.
If the RAM you chose is Value RAM, don't buy it. I did and it was a mistake. (CONSTANT BSOD's)
Everything else looks good, I would just change what I mentioned I think.
MSI 880G - AMD Athlon II X3 445 @ 3.72GHz - 4GB DDR3 1333MHZ DUAL CHANNEL MEMORY - SAPPHIRE HD5770 1GB GDDR5 - WD CAVIAR BLUE 500GB 7200RPM