I use plastic scrapbook cases that are see through and have a handle. I either separate my material by color or by holiday or by panels/printed or...... That way I can just pick the ones to go through when starting a project. I get them from JoAnn's with a 40% or 50% coupon so they don't cost too much. They stack nicely in a closet or on a shelf. :-)
http://www.joann.com/iris-usa-scrapb...false&start=12