I lived in London for 5 years,long story why, but this town is overcrowded for me. Only one thing I'm missing and you didn't mention is Camden Town and its pubs and bars. Great place where after sunset only the best people stay and party. If you know London, than maybe would recognize famous Dublin Castle pub, my favourite one. To be fair London is bloody expensive :P
You're right about London being expensive!! Camden Town is a bit off beat for me as I used to live in south west out in Surrey. I think I've only been once or probably twice
I lived in Isleworth and spent many weekends in Camden :)