For me this is a though question! So many to choose from and so different! London, Barcelona, Amsterdam, Paris, Prague! buff! is hard even for me to rank them :) every time i visit them again they climb on my chart. There is always something new or that you've missed the last time you were there.
Also depends on what you love the most when visiting a city, if its the strolling through streets with no destination or either that specific monument or museum you were dying to see for so long...
Or being more of a consumer it was that specific shop or restaurant you were craving for when you first planned the trip :P Who knows! The plan is to enjoy them as you like...
Here are some pics of my past travels,
With their colorful bikes everywhere,
Their really old buildings that endure time,
Lovely people enjoying well their sunny Saturday afternoon,
and of course cool vintage shops.
What do have for lunch? fish and chips!!
The coolest place to go shopping for any kind of affordable vintage, funk, retro item is with out any doubt Camden Town
you can also try there food from a lot of different countries,
and eat it with the best views,
In the afternoon why not go for a classic tea and scone at the Orangery
Walking next to the Thames river we end up capturing some interesting pics,
polka dot trees, techno parties,
really old pubs,
and the big ben by night,