[comex]

My 15" MBP at 1400x900x2 is wide enough to fit a split editor, or an editor and part of a terminal (I find that having part of a background window visible makes it less jarring to switch to it). I wouldn't mind it being physically taller, but I wouldn't want it to be any narrower.

[bjustin]

1440x900 is just enough for me to use Sublime Text 2 in two column mode, or Xcode with the assistant editor. I do have to hide any sidebars for both to be usable.

I stand by earlier post for, say, a web browser or email client.