Oh, I agree; you've gotta have as many weapons in your arsenal as possible. If I don't know for certain what sort of adhesive I'm faced with, I usually start off with Simple Green, then step up to Nature's Orange, Goo Gone, mineral spirits, lacquer thinner (toluene), then Goof Off.

If after all that, I still can't get the things off, I'm usually too stoned from the fumes to care...