Thames and beyond

If you spend 5 days in London and 4th is the first day you get to see Thames, Big Ben, London Eye and the Tower Bridge; you aren't exactly the best tourist in town. So don't get yourself nominated for the worst; and manage to get your butt there. The night view is even better.

Still, from personal opinion, I would suggest that the following are a bit on the redundant side if you are tight on time:
  - touring the Houses of Parliament
  - visiting the Buckingham Palace
  - riding on the London Eye
  - climbing the Tower of London

As long as you insert enough distance, you can put pretty much all of them in one pic, anyway :)