I use twm. It's pretty lightweight, it doesn't conflate "being on top of everything else" with "focus", and it's highly customizable. Oh, you can also handle

I use twm. It's pretty lightweight, it doesn't conflate "being on top of everything else" with "focus", and it's highly customizable. Oh, you can also handle ongoing-process-icons in a sensible manner that doesn't eat up screen space.