The green series hard drives run more slowly than normal to save power so theyre not great for gaming, i'd go for a blue series or a Samsung Spinpoint. Also, you can get some seriously decent RAM for just a few $ more. Look at the G.Skill Ripjaws X. Lastly i would reccomend losing the DVD drive if you can to get a case with no PSU then buy a decent one. (Antec/Corsair etc.) Other than that the build looks ok i think.