I would get the 13" MacBook. Thats the one I bought since my main computer is still a fast PC I just built a year and a half ago. The 13" is perfect size for travelling. Fits nicely in my backup I carry on planes. Oh, and now you don't have to take it out of it's case, as long as the case has nothing else in it. I just have mine in a sleeve so I just throw that right in the bin.
PS. I hate you
...unless you deposit some of that into my paypal account that is!