I've been fortunate to be able to travel to ~45 countries and live in 6. Out of those places, my favorite mountain location is Lauterbrunnen, Switzerland (Interlaken is cheaper to spend the night a few minutes down the road), favorite island is Corfu, Greece, favorite city is Budapest, Hungary, and favorite beach is a restricted military access beach at Tyndall AFB, Florida.
London was the most disappointing for me. While the historical aspects and architecture were cool, other things were not so great. There were few places open 24 hours to eat (and it was a weekend), drunks were stumbling all over the streets acting like fools and puking, younger people were mostly arrogant, and everything was expensive.