And each station will have it's own characteristic! In fact, for some stations wif multiple platforms, each platform has it's own "identity" (see Charing Cross and Baker which are excellent examples).
Here are some pics of these stations:-
King's Cross Station. Yup, the place to go to get your trains to Hogwarts - just head to Platform 9 3/4 - and mind the trolley that is halfway thru the door!
Baker Street - the oldest Underground station. take a closer look at Sherlock's head and u'll see it's amde of many tiny little heads! (The pic on the left above was taken by a Canon digicam)
Middle: Euston has one of the widest underground platforms that i've seen
Right: Elevated station for Docklands Light Rail - elevated most of the time (except when it goes under the Thames) - very much like our LRT back home.