Since you are going for Asrock you might as well get the z68 extreme4 gen3. If you don't care about the gen3 tech then perhaps gigabyte z68xp-ud3 is for you.
You don't mention an aftermarket cooler, i am going to propose the Corsair A70.
Get a lower profile memory or the A70 wont clear it.
If you can afford it, get a 6950 or even a 570. The 750watts is barely enough if you overclock the whole lot. I suggest 850 quality watts.
HDD? Either wd caviar black/seagate barracuda 7200.12/samsung f3. Sata2 or Sata3 don't matter, it will never get saturated and 32 or 64mb cache makes next to no difference. Floods in thailand make prices go sky-high. Find the best giga per $.