Been to London twice in October -- it was wonderful.

...and I, too feel a week in London is appropriate -- 5 days at the very least. You will will be glad you did.

My faves for first-timers:

Tower (takes a half-day to do right)
Westminster Abbey
Thames Cruise
British Library (not everyone's cup of tea)

...beyond that, there are so many other great things to do, you'll have a hard time choosing, even with 5 days...world-class free art and history museums, amazing historical sights, great theatre, super parks and neighborhoods for walking, etc.

Take the advice here and get yourself a couple of tour books. Then you'll realize that 2 days is insufficient. You have lots of time to decide.

SS

I'm hugely biased but you might want to think about doing Salisbury and Stonehenge by train and bus from London. Salisbury's about 1hr 40 on the train, and then there's a tour bus that takes you out to Stonehenge. Salisbury's much close to Bath than Stonehenge and there's a lot to see.

Re: the Globe Theatre, I did a 'behind-the-scenes' tour a few years ago. It was very good. When we lived in London one of the things we used to do was the walk from London Bridge Station, past the Globe to Waterloo. It always seemed to go down well.

As for other things to do in London - you might want to investigate/think about:
- Greenwich
- Tower Bridge
- the British Museum
- the National Portrait Gallery
- the Wallace Collection
- the Sundays markets - Petticoat Lane, Brick Lane and especially Columbia Road. They're all in walking distance from one another