A brand new Canon 5D Mark II will still run you about $2500 dollars retail on any website. A used Canon 5D Mark II Body over on eBay will still run you over $2100 dollars and that's not knowing it's true condition. Canon right now is running some specials on their Refurbished Equipment website with a 10% off Promotional Code bringing down the Canon 5D Mark II (refurbished) bodies to $1799. Yeah that's a pretty sweet deal for a full frame body with excellent low light capabilities. Sure it's a refurb, but it's coming from Canon with a 90 Day warranty.
If you're looking to pick up used equipment, I think these official Canon refurb units are still a safer bet than going for a used version off the auction site. Aside from the 5D Mark II, there's 7D's, T2i's, 60D's, and a bunch of lenses including L series refurbished. Promotional Code is fam211 and the link is here.