Favorite day trips from London?

Can I choose all of the above? :-) Seriously, all are wonderful. I think it would just depend on what you were more "into." Thinking if you wanted to overnight in Bath, you could leave London early, spend a couple of hours at Windsor (20 miles out of town, super quick on the train), then continue to Bath and spend the night. Windsor is basically right on the way to Bath. Canterbury is in the totally opposite direction, so that would be a stand-alone. Frankly, I think you will love which ever you choose.

Yes to all. We went to Windsor twice once by train from London and once by car on way back from Bath. Windsor can be seen in half a day. Went to Canterbury on another car trip. All are great sites, can't recommend one over the other.Enjoy.

I would say "Yes" to all three and add Salisbury and Winchester. The salisbury and Winchester cathedrals are top of my list of cathedrals, and would probably opt for both above Bath and Canterbury> Wincheaster has king Arthur's round Table (well..... they believe so), while Canterbury does have its hisoric and Shakespeare connections

Bath.

Bath

Depends on the WEATHER. Bath is beautiful on a sunny day, but those lovely white stone buildings turn to dingy yellow when they are wet. Both the scenery and the abbey (stained glass) need sunshine to be appreciated. Windsor is mainly indoors, so better for inclement weather. Another option (do you really need more choices?) is Hampton Court Palace.

Here's a link to an article I rewrote for TripAdvisor (after I was published in AAA Carolina's "Go!" magazine) about my favorite London day trips http://www.tripadvisor.com/Travel-g186338-c176673/London:United-Kingdom:London.And.Day.Trips.html

i guess it depends on the person Chani, my first visit to Bath was on a rainy day, and I loved it enough to go back twice now ! In Bath I enjoyed the Baths themselves and the Roman excavations.. all inside and spend a couple hours there. I then walked over to the church, I didn't even look at the stained glass( there is alot more spectacular in Europe) but I spend about 45 minutes just reading the memorial stones on the wall, very interesting. I then when and found a place for a tea and bun, then when to the Costume Museum for an hour..
So the rain didn't really ruin my day at all. It would have been nicer if it had not been raining, but in all four of my trips to London ( three of them in the summer) it has ALWAYS been rainy, just bad luck I guess, I do realize they have sun sometimes, lol , but I always find there is so much to do inside I just take an umbrella and deal with it( I even took a bike tour in the rain, buy the plastic poncho,, )

York is the answer long trip about 3 hours and not cheap but lots to see

It may depend on what you enjoy seeing. Bath is a great city, easy to spend the day--Roman baths, a lovely old Abby, a fabulous fashion museum and lots of interesting architecture. Windsor great if interested in palaces and English history. Canterberry has the wonderful cathedral and pilgram site and also the remains of an abby. Canterberry can be combined with Dover for a great day trip. Others to consider: Salisbury and Stonehenge or Stratford and Warwick.