Hi: I am planning buying a new macbook pro.And i think both 13'' and 15'' are very nice ones. One is for outstanding portability and the other is the great "i5" CPU and larger screen. So it is very difficult for me to make the decision. Then one day i watched some BMW ads and it helps me make the final decison. "GO for the 13''macbook pro". I think it quite make sense that: 13'' macbook pro=BMW 3 15" macbook pro=BMW 5 17"macbook pro=BMW 7 psf course you can customize your macbook pro and make them X, M ,6 OR whatever. SO personally i am very crazy about the BMW 3 series , it is not as powerfully as 5 and 7 series. But it is extremelly FANTASTIC. It looks very really nice and cute and "very easy to parking" btw. If you want more powerfully and luxury car, absolutly choose the 5 or 7 series. SO this is my crazy ideas about how to choosinng a macbook pro. Hopefully it can be helpful and please leave some thoughts and comments.