Both are 20 inch and have OSX Lion. The reason the newer iMac has lower specs is because it was an educational model. I'm not sure which to choose, also, does anyone know the value of each? Thanks!

iMac 1
-Early 2008
-2.66 Intel Core 2 Duo
-4GB DDR2 RAM
-ATI Radeon HD 2600 Pro 256MB

iMac 2
-Mid 2009
-2GHz Intel Core 2 Duo
-4GB DDR3 RAM
-NVIDIA GeForce 9400 256MB
-Airdrop capable