I have two 6-foot-tall book shelves full of gaming material. I own pretty much everything that was ever produced for the Greyhawk, Planescape, Dark Sun, Al-Qadim, and Birthright settings as well as a bunch of Ravenloft and Spelljammer and a little bit of FR. I still pull old 1st and 2nd edition supplements off my shelf to help with locations, NPCs, and background for my (on-again, off-again) 3rd edition Greyhawk campaign. In fact, right now I have a copy of the old 1st edition Greyhawk Adventures hardback sitting on my kitchen table.