OK, first. DDR3 is no use on an Intel platform because of the bandwidth limiting FSB. The supposed extra bandwidth that DDR3 brings is no use as the FSB bottlenecks. For example, say the FSB speeds is 400MHz, that's 12.8GB/s of bandwidth, which is equal to DDR 800. Increasing the memory speed will bring no performance increase due to the fact that the FSB is not "wide enough".
The Q9450 uses a 8x multi, meaning that to reach it's maximum overclock, you are going to need DDR 1066 to be sure you're getting the CPU's full potential.
DDR2 is so cheap ATM and it's the sensible choice as DDR3 is not worth it: http://www.newegg.com/Product/Produc...82E16820231166
And as you won't be going SLI, you can be rid of the Nvidia motherboard (I detest Nvidia motherboards). You'll get much better stability and overclocking potential with an Intel chipset: http://www.newegg.com/Product/Produc...82E16813136045
And it's not really worth paying extra money for a factory overclocked card, just buy the standard clocked version for cheaper and do it yourself: http://www.newegg.com/Product/Produc...82E16814130338
I like the HDD though
Oh, and one last thing, the PSU is overkill. Even when the whole system is overclocked, it will pull 350W max. A good 600W will be more than enough: http://www.newegg.com/Product/Produc...82E16817815001