I spent a happy hour looking at this site www.abandonedstations.org.uk/
The history of the tube is fascinating, and I love travelling on it, it is so atmospheric (apart from when I am commuting within London and then I hate it with a vengeance like any normal person reserving special ire for the wanking Circle line).
Some stations feel really evocative - for instance Lambeth North looks as if it hasn't changed since the second world war.