-Switch out the i5 655K with the i5 750, it adds another 2 physical cores, much better gaming performance, and you don't need the unlocked multiplier to get it to 4GHz easily.
-What's the PSU? it'd be good to know, seeing as it's the thing that will run your computer, and you need the best one you can get for the price.
-I'd go with this set
of memory modules, or this one
if you like blue. They have an extra boost in MHz and will give some added performance for a small price bump.
Other than that, it looks good, you don't really need anything better than the 5770 unless your resolution is 1080p or greater.