I had this same exact problem when purchasing mine. The 13" MacBook had everything I wanted internally, but I could not live with the screen size. I spent some time in the Apple store comparing a 15" screen to a 13" side by side, playing around with different applications and such, after which I decided to fork over the extra couple hundred so that I would be happy with the screen. I have a feeling had I settled for the 13" I would have had some regret. I definitely don't have any regrets with my 15".