One that's not so well-known is a surplus warehouse in Melbourne, FL called Astro-Too.
http://www.astrotoo.comThey're a clearing house (dumping ground) for all of the leftovers of the Kennedy Space Center/NASA/Boeing/Lockheed/Grumman/Northrop/United Space Alliance/Harris/Motorola/Florida Institute of Technology partners that flourish in the SpaceCoast.
I tried to throttle back the amount of visits I paid to that warehouse, lest my garage and office got too full. Last time I visited, they had gotten in a bunch of centrifuges, prenatal ultrasound machines, and at least a couple of those cosmetic blemish removal laser consoles. They had also started photographing and listing the more intriguing items on e-Bay.
A lot of the stuff still has government ID tags or government contractor ID tags on them, but the owner usually gives the government a bid on a tractor-trailer load of stuff, the government always accepts, and then he gets to wade through the mountains of equipment to organize it. I've found stuff from the Mercury/Gemini days of the space program there.