I think that when you visit London will visit many places ... I hope to visit all the places I have in mind! but I think that I would not miss for any reason would be the Buckingham Palace gate because this is a representative of the history of the United Kingdom.
Other interesting place to go is The London Eye because offers a unique opportunity to view all of London from the biggest observation wheel in the world.
I would also like to visit some castles and parks such as Windsor Castle or Kensington Gardens.
I really think you can not visit all these places in a week but dreaming does not cost anything.
see you London!