Up until now the only Mac desktop I've ever owned, except for the SE20, were headless ones. I've never had any problem getting a good price for them, and quickly. I'm thinking of going iMac this time. I like to refresh my computers every 1.5 to 2 years. Does the iMac retain value as well as the MP and MBPs? And do they sell quickly on eBay or tend to lag?