Most window-managers copy the ideas of windows and MacOSX these days. But some have innovative ideas, that make the life much easier and the work faster done.
I used long time Fluxbox - it was the first wm I learned to know, that allow me to configure keys and have control about the sizing of applications. Putting windows in a window-group and let them share the same titlebar makes the tab-feature of some applications unneeded - tabbing in the WM is the far better solution.
Recently I dropped Fluxbox - because I tried the awesome-wm. That makes life even better with this tag-concept. I can run applications in fullscreen without borders and without title-bar, that saves much space on the screen (good for my 8-inch-netbook-screen). I can tile the windows if needed and group tags together as I wish. I don't think I even use all features of awesome yet.
I want to know, what window-managers do you know with cool innovative features, that might change the world (at least the world of superusers).