I'm looking for a mac laptop. I'm likely going to buy it used, on eBay or craigslist. I'm completely clueless when it comes to mac, as every laptop i've had was PC. Is there anything I should look for or make sure I don't get? I want an Air but don't want a 13" or smaller screen. I think I want a 15" screen. I also found this listing on CL: http://columbus.craigslist.org/sys/2209035905.html I'd love to get it for the laptop, so I could have Office & CS5 but not sure what Macs it would work with. Forgot to mention what I want to do with it: - I do web design/programmer/a bit of graphic design so I need to be able to install quite a few programs like CS5, Office, and a few smaller ones. - Browsing the net I don't really use Itunes or need to store music.