Holy balls! I've found the best stuff in dumpsters. Actual dumpsters, too... not just recycle bins. By all means, raid the recycle bins... but don't be afraid to poke your nose into the trash, too. Stuff can be washed, and you don't have to take it if it's too soiled.
Some stuff I've gotten includes:
lots and lots of perfectly good clothes
textbooks that I sold back to the bookstore
over $30.00 in change, in an ugly purse that was thrown away
furniture (upholstered furniture is sketchy, but wood and metal chairs, tables, etc are fine)
a very cool 70s tuxedo jacket with tails
I don't do it much anymore, because I don't need much stuff. But I still like to hit the fraternities and sororities at the end of spring semester, to get textbooks to sell back to the bookstores. I've made a good bit of pocket money that way.