I don't have enough money to get a brand new Mac right now but I'm going back for my masters and need a portable laptop. Right now I have an iPad 2 and a MacBook pro 2008 2.4ghz 500gb. I can either buy a used air or MacBook pro on craigslist that's newer than what I have, or I can upgrade my pro with a 550gb solid state hard drive, 6gb of ram and a new battery for roughly the same amount. What would you do? Or would it be another option that I haven't listed? Any and all help would be awesome!