The second coffee shop has to be Kaffeine. Having only recently come across this one, I was certainly impressed and they may even have the best coffee I've had, since a short stay in Portland, Oregon.
London is so vast I end up spending hours travelling on trains. They are by far the best way to travel around on and are always full of weird and wonderful characters.
London has plenty of beautiful cemeteries. Brompton is one of the ‘Magnificent Seven’ and has many interesting tombs. It was also an inspiration of names for Beatrix Potter and the resting place of Emmeline Pankhurst.