I bought these metal cutlery trays at Target on sale for about $5 each. The bottom and sides of the tray are dotted with evenly space holes, so nailing them to the wall was a breeze!
I like the way I can easily view my paints without having to open and close 6 different drawers (my old storage system) in order to find just the right color. I keep a small step-stool handy, so reaching the paint at the top is not a problem.
Floor and counter space is more important to me than wall space, so this system works well for me.