Annie Mole's, webmaster of Going Underground, daily web log (blog).
If you like this you'll LURVE One Stop Short of Barking, THE fun and informative BOOK about travelling on the London Underground.
Click on this page and you'll see the map in various stages (well, current & new). I'm guessing that TfL will never show the lines in this way, which is a pity, as it would make a lot more sense of the orbital railway and links with the London Underground.
Who's for a massive Circle Line party, when it's all finished?
"The magic, mystery & sometimes maddening shortcomings of London's Tube are documented with love, enthusiasm & sometimes despair by its unofficial social historian." The Guardian