Starting place for the Harry Potter tour! The tour takes 1-2 days to complete, but it might be good to stretch it to three to actually do some of the attractions that you pass on the way (like the Tower of London or the Globe). Best part, it's free!
Chinatown in London: Explore the restaurants, bakeries, night clubs and enjoy the great atmosphere of Chinatown. Well worth a visit. Detailed information http://www.tripomatic.com/United-Kingdom/Greater-London/London/Chinatown/