I'm not nearly as well traveled as I'd like to be. It's possible I've toured more European cities than American cities. I loved Amsterdam, but not for the reasons most of you would think. I liked Los Angeles. I liked New York City. Seattle is probably my favorite North American city. Boulder, Colorado is a gem. I also enjoyed San Francisco. I've been to Vienna and I thoroughly enjoyed it. I've been to Berlin which was nice, but seemed too big. I've been to Frankfurt.
But my favorite city by a long shot is Munich. I basically lived in Munich the spring and summer of 2003. Some people say that Texas is friendly. But, in Texas, it's hard to find a place where you sit shoulder to shoulder with strangers, drinking beer, singing songs, and eating pretzels and sausage. In Munich, it's hard to find a place where you don't.
Here's a good article to read when you have time.