SSD's are primarily good for quicker launches and load times... but not so much for data.
Keep your O/S, Browser, Media Players, Office and drivers ... all on your SSD...
Relocate your Videos, Pictures, Music, and Downloads to your other drive..
I would also use the mechanical hard drive to install all your games and misc/general programs on... that will save the save on your SSD and allow your Image Backups to complete in a matter of 1-5 minutes.