Espion you can actually put steam on an SSD and then put the rest on your storage drive using
Steam Tool. Have you optimized your SSD for storage? You can cut out features you do not need to gain quite bit back, see this
here. You do not have to put every game you own on an SSD as not every game takes advantage of the load times. Even if you load quicker in a FPS for example you still have to wait for the round to start depending on the game. I have about 35 GB of games and Office installed on my 64GB SSD and have no problems using it. Just have to be smart about the games/apps you put on them.
EDIT: I made a $1250 build version including a 128 GB SSD for those who wanted something above a 64 GB one. Though the build will be slightly more expensive depending on the case and any shipping+taxes.
Please don't merge the post of mine below this as I maxed out the char list in the OP and I moved the case list to another post.