What I'd like is an interface that is primarily graphical, but keyboard-centric rather than mouse-centric. The Debian installation interface is quite close to the concept I'm looking for, if a bit simple.

The main thing I use my laptop for is mathematical scripting (mostly python) and I often find the traditional windowing system to be a tad cumbersome, especially on such a small resolution (1024x600). I actually purchased this machine as a replacement for my graphing calculator, and I'd like to find some kind of interface that's similar in concept, but a bit more expansive with split-screen capabilities.

I have no idea exactly how clear I'm managing to be, but what would you recommend? I'm currently running Debian with the MATE desktop, and Spyder for my python scripting. Is there a way to install multiple UI's and just switch between them?

Xmonad.

Ratpoison.

Adding to the list: i3wm.

... and there's always Emacs.