I know this question has sort of been asked before, but I'm looking to get a laptop to supplement my desktop for app development. I'm anticipating it will be used to bring to developer meet-ups, client meetings, or whenever other family members need to use the iMac. So that being said, how difficult is it to code on a 15" screen? I will guess that for anyone out of their twenties the 13" is too small, but what do you guys think? Do you spend all your time closing the Navigator and Utilities panes and scrolling code panes around? Is the type too small to comfortably read on the laptop? I'd really appreciate any comments. The Apple Store has the 13" and 15" MacBooks on separate tables and Xcode isn't installed -- plus it's hard to spend serious time evaluating the screens with all the bustle there. Thanks!