I find that using a charm pack can actually help me with de-stashing.
I do buy 2, usually, when my plan is to make a full sized quilt. Then I put them up on my design wall and get a feel for them. Some blocks or colorways I may pull, if they're not working for me. Then I go through my collection of small scraps and pull out anything that I think may work. I love mixing some of my old stash in with the new stuff. The resulting quilt is more unique than one that's just a working of the original charms.
Even if I do have a few squares left out, they're easy enough to use up in a future project. 5 inch squares make great bean bags or a couple o coordinating ones make great coin purses.
There are some really nice patterns specifically for use with 5 inch charms. One of my favorites for a quick but impressive gift quilt is Chain Linked. 2 packs of charms plus yardage of 2 contrasting solids, and you have a modern, graphic, easy-to-piece and assemble twin sized quilt.