LOVE IT!!! I've found some of best crap I ever bought at Goodwill stores, most recently I got a Nickelodeon "Super Slimer" for $4.99, a book on early digital artwork and some crazy new-age Christian book called "After The Rapture" from the late 70's.
I always force my folks to go the local Goodwill store wherever we go for vacation, I got a unopened McHammer CD and a couple of Genesis games up near Cedar Point.