To be fair though, it gets a lot of shit and yet is one of the most comprehensive, best run systems in the world.
I've only ever experienced comparable (well, better) at the same sort of scale in Tokyo, and that is expensive too (though commuting is normally covered by your company).
yay, go london ! ( said in an unconvincing voice gradually fading away )
http://www.independent.co.uk/news/uk/home-news/london-has-the-most-expensive-public-transport-in-the-world-10475558.html
top of the table