I have a dormant obsession with Amsterdam. (Not for the reasons you may think, though I enjoy that aspect of Amsterdam as well ;-)
What really made me fall in love with the city was the bicycle culture. While numerous - it's widely said bikes outnumber human beings in Amsterdam - it's nothing like the mass-biking death wish hordes of certain Asian cities. While part of a cosmopolitan city, it's a far cry from the hipster-on-fixie or critical mass madness of San Francisco. No, Amsterdam is dotted with quaint looking "city bikes" - kind of like cruisers, but more Euro than say Venice Beach, if that makes sense.
A Continuous Lean recently featured a collaborative effort between Gant and The Impossible Project, and the result is an absolutely gorgeous city bicycle (see below).
It's fit for the most bougie of European cities. What I loved in particular about the culture and bicycles found in Amsterdam is that bicycle use is not limited to a particular type of person (as it is in San Francisco for the most part). You see gents in suits, women in dresses, hipsters, old people, kids, basically anyone and everyone. And somehow everyone is civilized enough to make it all work - I didn't see a single mishap in my three days there despite literally thousands of bicycles weaving through the city.
Pictures from my trip to Amsterdam, Summer 2009