I'll second QM's suggestion to just sticking with one WD internal HDD.
Without overclocking, the stock Heatsink and Fan should be more than adequate. Also, is there a reason why you are going to buy a six core? Games are more GPU dependent than they are CPU dependent. If you want to make a decent gaming machine, a strong dual-core or even quad-core should be fine. You should probably really look into spending more on a video card and less on a CPU.
ASUS P7P55D-E | Intel I5-760 @ 2.8GHz | Corsair XMS3 8Gb @ 1333MHz | WD Caviar Black 1TB | HIS Radeon 6850 | Corsair 750TX 750W | ASUS 24x DVD Burner | Antec Nine Hundred | ASUS VW246H 24" | Windows 7 Home Premium 64-bit