The Tate Britain has those work by two outstanding non-British artists, John Singer Sargent (Carnation, Lily, Lily, Rose is sublime) and James McNeill Whistler (Nocturne: Blue and Gold, Old Battersea Bridge should make every Impressionist envious). Try to get one of the free docent tours. The master of light and sea, J. M. W. Turner has his own addition to the Tate, the Clore Gallery.

Somerset House, the home to the Courtauld Galleries and, on the river side, The Hermitage Rooms (A Rubens show starts Sep. 20), is a spectacular renovation.

For a treat visit the Dulwich Picture Gallery. It's a gem, and a short train ride from Victoria Station and a lovely little village for a lunch. A special exhibition, Shakespeare in Art, is on until Oct. 19. http://www.dulwichpicturegallery.org.uk/

I don't think anyone's mentioned the Museum of Mankind. I always love the changing exhibtions there. They have the shrunken heads too. It's not a very big museum so doesn't take much time to see but is really worth it.
Have fun :-)

Mischka:
What is in this Museum of Mankind and where is it? This is the first I have ever heard of it.

The ethnographical/anthopological collections of the British Museum were housed there for at time, but they're now being reabsorbed back into the BM main centre
http://www.thebritishmuseum.ac.uk/ethno/ethhome.html

To help you to decide, check out the special exhibits at the museums you are considering. If you're torn between the British Museum and the V & A, for example, the fact that one has Cleopatra and the other Art Deco this month may just be the deciding factor.

Remember, too, that the churches are in many ways museums as well. Reading the memorials gives a wonderful sense of British history.

If you love theater, don't miss the Globe exhibit. Even if the theater season itself is over, this recreation of Shakespeare's most famous venue is worth a look.

Have a great trip.

I have this same question - thanks so much for posting it!

What do people out there have to say about John Soanes' museum & Daniel Severs' house? I've been considering those as well...

Went to London in May. My husband and I loved all the museum's we went to. Would highly suggest the John Soane Museum. Be sure to go when they have the tour. Don't think we would have enjoyed it as much if we didn't go on that. Another tip is if you go to the National Gallery, be sure to make a reservation for lunch or dinner at their restaurant. Our meal was fabulous! (A bit expensive but was worth it.) Save room for dessert, too.

Suddenly dawned on me, what about the Museum of the moving image, MOMI, surely one of the best if not the best of it's kind in the world?

Hi,
A Museum to save for later is the Design Museum by Tower Bridge- has it's own website. If this is your sort of thing you'll love it.
We also love the Bethnal Green Museum of Childhood. These two places can't really compete with the big guns but I adore them. But Museums are a personal thing - my husband will stare at old rocks all day whereas the Egyptian Mummies do it for me every time.
The Tate Modern causes mixed reactions - but the great thing about it is that it DOES cause reactions! Not a place you can leave unmoved, whether you loved it or hated it.
The National Portrait Gallery gets my vote but there again a personal thing - I find these pictures intriguing, and as it's fairly small you could swish round and just stop by the bits that really appeal - to me it is the famous Bronte portrait with Branwell painted out - I have to be dragged kicking and screaming from this......
Have a lovely trip.

MOMI has closed.

Dennis Severs was always very insistent that his house was not a museum and he was not offering a 'tourist' experience. His book '18 Folgate St' is quite vocal on the topic..Whether the present curators have the same idea, I don't know. www.dennissevershouse.co.uk

PatrickLondon, Has MOMI closed permanently? I thought it was scheduled to reopen sometime this year.

Thanks for the information Patrick. I was planning to visit again in April.
Luv2Travel I hope the museum is open by the time you visit.

A web search on MOMI just turns up some stuff from the British Film Institute which doesn't say anything about re-opening it (the running of the BFI is a saga in itself AIUI). They're offering actor/animateurs on a consultancy basis under the MOMI name, but that could mean anything.