The problem will people and SSDs, is too many want to absolutely "baby" the SSD, by moving this and that off the drive to a SLOWER HDD.
Use the drive for what it is meant for: FAST access times. Leave all Windows files/settings on the C drive. Wouldn't you want the fastest access to these files?
There is ALOT of stuff in the "Users" folder, as I'm sure you noticed. Most of the files/folders are hidden, like the Temp. Internet folder.
Have the OS and Programs on the SSD, Data/Media on an large HDD, and backups on the huge HDD.