namesalano :
Would you be able to use an SSD as a main drive for Gaming? Maybe a 120gb SSD?
Yes, but...
Seriously consider a larger drive. 120GB goes away pretty fast.
What other drives will be in this?
For a single drive in a game system, you really need a 500GB drive. Some of the newer games run about 100GB once you include the DLC.
If there are other drives, look at a 250GB for the OS drive, instead of the 120GB.