I've sold several things on ebay. What I've found is that electronics and items that are still new in the box fetch solid prices. For example, I sold a Magic Bullet Blender that I received as a gift two years ago. It was still in the box, never used. Stores sell it for $49 and I sold mine for $34.
I'm also looking to sell an old netbook (www.cashforlaptops.com offered $68), some furniture (probably on Craigslist) and my Dad's old coin collection. I have mixed feelings about selling the coins since he left it in his will for me but it's not really doing me any good sitting in a box in a closet.
The biggest possession I might sell is my 2009 Pontiac G5. I'm still trying to decide.
It's amazing how much money I can raise this way. Money that goes toward paying off debt and moving. Even better, there's a liberating feeling in getting rid of things that are just sitting around my house gathering dust.