@Michael-O-Reilly0 , living in a big, bustling city, I've got nothing to compare to the amazing views that you and other hosts have posted here.
I have hosted such a wide variety of guests, with different interests who come to London for many different reasons. There are also so many things to do and see here, it's really impossible to pick one favourite.
One of our local pubs is considered to have one of the best pub kitchens in London, serving very high quality seasonal British food, so I have sent many guests there. We also have a really good Indian takeaway nearby that guests seem to get addicted to once they have tried it. The most popular dish in the UK is, after all, curry.
In terms of museums, people who come here often visit the British Museum and the Natural History museum, which are both amazing of course. In terms of art, they go to Tate Modern and the National Gallery.
However, few think to visit the original Tate gallery, now called Tate Britain, which is a quick journey from my house. They also don't realise that the National Portrait Gallery (currently closed for renovation) is right by the National Gallery and very well worth seeing. It also has a restaurant with amazing views of London (that unlike the often visited Shard, doesn't require buying an expensive ticket). The John Soames museum is quirky and really interesting. My favourite of all is the Victoria and Albert Museum, or V&A, which is right next to the Natural History Museum. I don't know how many times I have been there but I never get tired of it. The exhibitions are fantastic but the building itself is stunning, even the cafe.
Of course, it's well worth seeing the best known sites in London such as the Houses of Parliament/Westminster, St Paul's Cathedral or the Tower of London, but I do love recommending amazing places to guests that might not be on their radar.