While we're talking about maps, here's a neat little gimmick from Andy Hudson-Smith of the Digital Urban blog. Not only does he lay out the Tube geographically (in itself nothing new), he also has a stab at making it three-dimensional, adding key buildings for effect. What he really needs on there is a sense of depth. Unfortunately, security issues bar TfL from releasing this information. Perhaps we should all count the number of steps down to platform level at our local stations and email Andy the results.
Full screen map here.