I’ve been using single window mode as recommended in this article. When you click on a window in the dock then all the other applications are hidden leaving the selected application as the only one displayed. Here is how to enable it from a console window:

One recent benefit is that hidden apps go into “Nap mode” to save energy. Plus, it is just nice how the screen gets cleaned up. Using ⌘-TAB switches between apps but keeps previous apps on the screen much like the usual behavior. However, as soon as you click on an app in the dock then all the others are hidden.

I liked it 85% of the time but cutting and pasting between apps and apps displaying modal dialog windows frequently got lost and difficult to figure out what was going wrong. After about 6 months I’m disabling it: