I run iTerm2 in full screen with Vim split alongside 2 or 3 console panes; I find the separation from the rest of my OS a blessing. The second screen I use for Chrome, HipChat, Flint, Sparrow etc; I still notice chat notifications, and to keep a eye on my dock (which displays all notification counts across my multiple programs) is a simple key combination if I'm in 'the zone' and don't wish to break out of my programming environment (iTerm2).
I've tried larger screens in the past, and found myself physically looking around the screen a lot more, simply due to having all my content splatted together.
Combine this with a keyboard-based window manager and the 1/2 - 1/4 screen segmenting and I feel much more organised and efficient than trying to manage a 30"+ monster of a screen.