I may have the chance to visit London later this year from the US. I have been once before about 6 years ago. I plan on visiting Bletchley Park. Any other suggestions of what to see?
Trip adviser has lots of reconmendations. Tower bridge is worth a visit, but I've only ever been to london once, for a weekend, so I cannot add that much more than this.
But Bletchley Park isn’t in London.
But Bletchley Park isn’t in London.
I realize that. It is only a short train ride away.
Pubs, that is all you need to see 
Science Museum
Natural history museum
Victoria and Albert Museum
All together in Kensington and well worth a look.
Tate Modern
One of the best modern art museums in the world.
Design museum, Close to Tower bridge.
I didnt think Id like this but it turned out to be very good.
Gordon
There are some great bookstores in London. And Harrod's...
(You can get Terry Pratchett in the original British!)
Thanks Gordon.
I hadn't heard of the Design Museum, but it looks like something I would like.
Stop by Greenwich Observatory maybe? Nice view, there's a planetarium there as well I think...
Would definitely recommend the V&A - they've always got something good on.
Hello again!
This morning I read a magazine article saying that they were re-building one of the first ever computers in the computer museum, at Bletchley Park.
http://www.bletchleypark.org.uk/edu/collect/computer.rhtm
The magasine article was in BBC Focus,
I would defiantly recommend Foyles Book Shop the one marked A
http://www.foyles.co.uk/book-shops-in-london
It is close to Denmark Street where all the mulsc / music tech shops are.
Not a lot of people know you can get a guided tour of Parliament and a trip up Big Ben. Even if you're not into politics (like I'm not) it's still a very interesting experience. Best not have an arduino and dangling wires in your rucksack as security / searches were similar to an international airport when I went. It also says book in advance....
http://www.parliament.uk/visiting/visiting-and-tours/tours/
http://www.parliament.uk/visiting/visiting-and-tours/bigben/
and a trip up Big Ben
He means the Palace of Westminster Clock Tower, sometimes known as St Stephen's Tower 
I may be wrong, but you can only go in to the parliament and big ben if you are a british national.
If you're an Arthur Conan Doyle fan, you can always visit the 221b, Baker Street. There's a tube station close by.
For lunch, during weekends, I'd recommend Borough Market right next to London Bridge (do not confuse with Tower Bridge) or Greenwich Market.
He means the Palace of Westminster Clock Tower, sometimes known as St Stephen's Tower smiley-wink
Sounds like a tour guide on one of the many open topped buses we had when we went a few years back. His other major was "Do not feed the flying rats" - pigeons......
...or the tree-rats (grey squirrels)