I stumbled across
this article via the 37signals blog. Apparently, a graphic designer took it upon himself to redesign the (horrifically complex) New York City transit map to make it easier to read. IMO, he did a great job, geographical distortions notwithstanding. It's a really beautiful map, and every other city I've seen distorts their subway map for clarity.
The coolest part: the guy who designed it is from my hometown!