What should I put on my SSD?

Solution
You don't want to fill the SSD up else it'll stop working properly. I just keep the OS on mine. There's 30GB to spare on it. I plan to keep it that way.
I get machines back here all the time with full SSDs .... even when you put ya programs and games on other drives, they oft like to dump "common files" on the C:\Drive. That's why I am using SSHDs more and more.

120 GB SSD boots in 15.6 seconds
4TB SSHD boots in 16.5 seconds
 
i wouldnt bother with anything less than 240gb for my main drive, it would fill up too fast. My hdd is partitioned with a 250gb primary partition for OS and programs, and it only has about 60gig remaining. Games take up a lot of space these days, as does a windows install +updates.