Well, I've been outclassed. The Tube Journey Planner not only maps the tube very nicely but integrates real-time problem information as well.

Technically, they are cheating a bit. They're using edited background images to show the tube lines. Hence it's not easy to modify (not a problem in London as our chances of getting another tube line are non-existant) but the line lines are smooth and look really good. And the redraw is nice and fast. Downside - the map stops at the end of the tube lines - the world outside has vanished (and a good thing, too).

Neat toy though, very nicely done. And it does set quite a high benchmark.