Favorite Daytrips from London?

Salisbury and Stonehenge by train. Hampton Court and depending on the season, train to, cruise back, vice versa or simply train out and back. Windsor Castle.
Oxford. You asked for favorites though. Mine would be Stonehenge (which some folks find a bore) and Salisbury. Second vote for Oxford.

As noted by others, I too was underwhelmed by Stonehenge. Brighton?

Cambridge is lovely and interesting.

I did a combo of Bath and Stonehenge. The latter was an interesting stop, but the highlight for me that day was Bath. I would have liked to have seen Avebury that day, but it was cut out. Oxford was also an impressive daytrip.

I'm among those underwhelmed by Stonehenge. My favourite day trip from London so far is Winchester.

Have 3 days each for Bath and York. Have two days in London where I can do daytrips. Thanks all so far for the suggestions.

I am confused as always, LOL. If you have several days in Bath and York, you only need day trips from London, correct? If so, then would do Windsor, Hampton Court, in my opinion.

A few years ago I wrote an artile for AAA Carolina's "Go!" magazine about my favorite day trips from London by train. I recently re-wrote it and posted on TripAdvisor- here's a link
http://www.tripadvisor.com/Travel-g186338-c176673/London:United-Kingdom:London.And.Day.Trips.html

Stonehenge- very moving place in my opinion. Salisbury, Winchester and canterbury cathedrals- all easily by train. You could possibly do Slaisbury and stonehenge from Bath ( i am not that excited about Bath- so three days is not needed there) also consider cotswolds from Bath Hampton Court by train from London (we do that every time we are in London- always seems something new to see), Windsor by train from London- both comfortable and easy day trips. Oxford and cambridge are also do-able, but Cambridge is easier than Oxford if you are not on a tour

Thanks for the kind replys.

York longer ride 3 hours as I recall but great things to see.

Bath, Stonehenge and maybe Salisbury make a great full daytrip from London. You can substitute Avebury for Stonehenge but I think you'd be sorry to miss an iconic site. True, Stonehenge is just a bunch of big rocks in a circle but Avebury is essentially just smaller rocks in a larger circle. For an easier daytrip, Oxford is a good choice. There is a bus (I think called the Tube) that gets you there and back quickly. Once there you can wander, shop, visit a school or see some literary sights (Harry Potter and/or Alice in Wonderland).

The Area around Chichester in Sussex. A lovely cathederal to visit, followed by a tour of the Roman Villa at Fishbourne and a visit to nearby Bosham harbour to visit it's Saxon Church. If you chose to make it a two day trip you could attend a play at the Chichester Festival and then go on to Portsmouth to visit HMS Victory and the remains of Henry VIII's ship Mary Rose.

Lots of great choices. Can't wait to go.