You can setup how ever you want.
SSD's are nice and fast so as long as you can get by with your files/programs on the SSD, go for it.
As with any drive, keeping a backup of personal files is ALWAYS a good idea. SSD's and HDD's can fail.
I personally have a 256 gigabyte SSD for Windows another for some extra programs/games a small 64gigabyte SSD for Win8 and 2 TB drive for files/documents/desktop/ect. I have another identical 2TB drive in an enclosure for backups(on for backup, then off to keep it as an offline backup so to speak.).