First Set up, compatible?! SSD and HDD?

Hello, I am going to ask all of you experts on your opinions of my pre built set up. First, i am using my MBP Retina 15.4" that i got not too long ago which has a 250gb SSD. And ill add, it is VERY quick, starts up in a few seconds and is flawless, minus gaming. I know i can add bootcamp, but two OS and then downloading games and all the other stuff leaves me with no storage. So first, I currently plan on buying a HDD (1TB Western Digital 7200RPM, 64 MB cache) for my new computer. How does having two hard drives work? Do i put Windows OS on the SSD and maybe two or three games on it and then everything else on the HDD? In that case, i would probably go down to a 500 GB HDD and maybe a 128 GB SSD. What are your thoughts on that?

Heres my plan on what i would like to purchase and build. Is it compatible? Is there enough/too much power? 750 W

i7-3770K
eVGA GeForce GTX 670 FTW
ASUS P8Z77-V PRO
Crosair Vengeance low profile 8gb (2x4gb)
Crosair HX series HX750 - 750 Watts
Western Digital Black 1TB 7200RPM 64mb cache
Crosair Carbide Series 400R
Crosair Hydro Series H100 <------ Is this necessary?

BTW, this computer will be used 99% for gaming such as BF3, Arma, Far Cry etc.....