London has some great museums. Definately check out the British Museum. It was re done awhile back and is very impresive. I was briefly at the Design Museum around Tower Bridge. they had some cool stuff in there. it is basicly a salute to all things designed well. is the empeg in there?

typical stuff that i've taken visitors to: the london eye is a good experience, but costs c. £10. if you go on a nice day its worth it. The Churches, Westminster Abbey and St Paul's, are not very expensive, if they cost anything. Tower Hill, is also c. £10, but is interesting esp if you like history.

hope that provides a good start