My parents used to live in London proper and I visited them. I've also been there twice since then with a third time this summer....there's so much to see and do!! I love this city!!! You can go to
www.londonpass.com, which will give you an opportunity to see what you can do and the costs. Depending on how long you'll be there, the pass may be beneficial for you...
If you want more specific information, PM me!