Space is a consideration for me. I also like to see all the shapes and sizes. I got a little creative. I used pushpins and made up groupings on the walls in areas that were accessible 'dead space'----behind the door, between the closet and bookcase, and some inside the deep closet and hung them that way.
I'm getting ready to move, lease is up and we're not renewing, so where ever I get to set up again, I'll come up with a way to store the smaller rulers that can't hang that currently are in a drawer, hidden, and I don't like that.
Oh, this way with a push pin, it doesn't leave huge holes. I don't have the floor space for a holder nor do I have table space to accommodate all my rulers.