I recently just finished my first desktop build (it went easier than expected) and my boot drive is a 120GB Samsung 840 SSD. 120GB isn't a lot of space for games.
Currently I have my MMOs (World of Warcraft and Star Wars: The Old Republic) on my SSD, but no other games.
I plan on getting a 1TB VelociRaptor drive for games and programs, and a 2 to 4TB WD Black HDD for music and movies.
How do I install games onto the VelociRaptor or other programs on the WD Black?
Edit: Also, how do I choose what hard drive to boot from? I also have a 1TB HDD from an old laptop that I have programs on for school. Sometimes I want to / need to boot into that. How do I go about doing that? Both the 120GB SSD and the 1TB HDD have Windows 8 on it.
As far as installing games on other software on the HDDs you can create the Program Files (x86) and Program Files folders (only both in a 64 bit OS) on the HDDs. When you install a game or other program you can choose to install it on the HDD of your choice. Booting from the 1TB drive might be an issue because it won't have the same system drivers as your recently build desktop. The 1TB drive will have the motherboard (sound, video, etc.) drivers for the laptop. That doesn't mean you won't be able to access files but accessing programs could be a problem. That's not to say there may not be a way around it but someone with experience doing it will have to help you.