Last year I got a big monitor, because I thought it would boost my productivity. It did, but only after I added a special piece of window management software.
I got a 22 inch Samsung with a resolution of 1680×1050. This was a mistake: To really boost productivity I should have bought a bigger one. 1920×1200 seems to be the sweet spot.
But what really struck me is that I seemed to spend a lot of time shuffling windows around to get the applications I wanted displayed next to each other. If anything, I felt less productive.

A tidy desktop, organised with Winsplit Revolution
I found a piece of software called Winsplit Revolution, courtesy of LifeHacker. It lets you get windows into predefined sizes and positions quickly. Configuring the positions is still a confusing and manual process but it’s worth it. With intuitive key combinations I can now snap windows to top, bottom, right or left, and toggle through 66%, 50% or 25% sizes. This means I can get practical window layouts easily.
Looks like this kind of idea is included in the Windows 7 window manager. I suspect OS X users could benefit from something like this too, although Spaces might also act as a a solution to this problem.
See also…
This is one of the reasons I am a bit scared of single wide screens, it feels like you would have to spend time shuffling windows (as you mention). While that app probably helps things out, I still prefer the feel of two discrete screens, which come with edges, and easy to pop apps to full screen. I think multiple desktops helps (spaces on OSX, or every gui on linux
, but being able to put edges/sticky bits on a widescreen is a good middle ground.
You can also “On Windows you can tile windows without any extra software. Just select as many open windows as you want by Ctrl+clicking them on the taskbar, right-click and choose “Tile Horizontally” (or Vertically).”
or use Gridmove:
“GridMove is a program that aims at making windows management easier. It helps you with this task by defining a visual grid on your desktop, to which you can easily snap windows. This program comes bundled with some predefined grid templates, that can be easily swaped, but also has ways of creating custom grids or sharing grids made by others.”