I'm looking for the functionality that you can find on window managers like awesome, screen, and tmux where you can specify the window you want to switch to with a directional key.
When using applications one at a time, it makes sense to think about them as a stack and navigating that stack using alt+tab is a good workflow.
However when I have more than one (in my case about 5 across my 3 monitors) application fully visible it is no longer a trivial task to switch to one that is in a particular position. I can see it, yet my choices are to either pick up the mouse or hunt for it in the alt-tab-switcher menu, neither of which is ideal considering the simplicity of what I want (which is to move to the next window to the left or right which was last active -- note that last active means that it is top-most visibility order).
Are there any programs that can detect the position of active windows and gives shortcuts that can intelligently do this sort of switching, on either Windows or OS X?