What do you guys think? I'm trading my Late 08 15" Unibody Macbook Pro 2.8Ghz, 320gb HD, NVidia 9400M 256MB Graphics Card, and 4GB DDR3 Ram for a 2012 Macbook Air 13' Intel i5 1.7Ghz, 4GB DDR3 Ram, and 128GB SSD. But I do have to put some cash on top for the trade. I'm thinking my MBP and $150 on top? Is that a good deal or am I getting ripped off?