On my way from Perth, Australia to Germany I did a free stop over for days in London. There is so much to see in this beautiful town that this visit was just inspiring me to come back with more time.
Favourite spots:
The national Gallery is an incredible place. Definatelly worth a visit. Check out Herolds a famous store in the down town. Even at night it looks just awesome from outside
What's really great:
For sure not the prices :-) The double level busses are pretty nead.
Accommodations:
No matter where you try it you will spent lots of bucks for the overnight, except you know somebody (or get to know somebody :-) or you sleep in the great city parks :-)