I would like to start off by saying that there's nothing just inherently wrong with the build you listed here, it will work as is. That being said though there is still considerable room for improvement and you really should state your budget so we know what to work with.
First, the CPU. If you ever plan on overclocking (you said "could be") you need to get a CPU with a K designation, which means the CPU has an unlocked multiplier. As it happens, the 2500k is only $10 on Newegg than the base 2500. I highly suggest just getting the 2500k to keep the overclocking road open.
Second, your GPU. The AMD 6790 is priced about roughly the same and will outperform it.
Third, you didn't mention the possibility of SLI/Xfire and the mobo doesn't support it. So, there's absolutely no need for a 750 Watt powersupply. That's overkill and then some for this build. 450 Watts would be more than enough for this build.If you want a great power saver one I can't suggest this one enough...http://www.newegg.com/Product/Product.aspx?Item=N82E16817371054
If you're absolutely wanting a modular one check this one out...http://www.newegg.com/Product/Product.aspx?Item=N82E16817256065