I've never found a window manager I've been 100% happy with - KDE and Gnome are far to slow to live on my old P600 Laptop, Afterstep, while asethetically pleasing, had too many menus, too many different feels and options and and I never could settle on a consistent set. Ratpoison was my most recent discovery, and while I liked it for it's simplicity, it was a bit too simple - it handled modal dialogs like mozillas download manager dialog badly - putting them in a whole window. At last I've discovered Ion - a tad more sophisticated than Ratpoison, but not much, so it still responds instantly on a clapped out laptop. It just handles dialogs much better, and works on the same principe - you should be able to treat your window manager in exactly the same way as you treat your text editor window - by having multiple windows and frames you can split, delete, create, and traverse between via simple keystrokes. If you dislike mice, it's worth giving it a try..
The only problem is -- there will never be a Windows version. It'd be interesting to see what a Mac user would make of it, though..