Cheezy the Wiz
Socialist In A Hurry
I have to say I don't really see why the Houses of Parliament (that is, the palace of Westminster) or its clock tower (Big Ben being the bell, of course) is really such a great building. It may be iconic but really, it's just a clock. The London Eye, directly opposite, is more impressive as a structure.
Isn't it just a giant Ferris Wheel?
If you're looking for impressive, how about St. Paul's Cathedral, or Salisbury Cathedral?