[Maximal]

I have used a Macbook Air 13" (i7 2GHz, 512GB SSD, 8GB RAM) for over a year exclusively for software development. The machine has been great, except I am frequently swapping windows back and forth, because of the screen resolution (1440x900).

I develop using numerous tools including Emacs, Xcode, IntelliJ, WebStorm and Visual Studio (running inside VMWare Windows 8 Pro). I have never noticed any lag whilst coding

Would I buy the same size machine again? Yes. The trade off is weight against screen size, although I think a higher resolution screen might put a strain on my eyes considering how long I use the laptop.

For me desktop was never an option, because I code on the train often. I also do not use either an external monitor nor a keyboard.