What is your favorite US city you have visited?

I'm intrigued by travel.  I love spending a few days in a city to get its vibe.  Every city is diffent.  I grew up near Philadelphia which to me seems a little dirty and angry but a hint of history.  I visited Pittsburg and felt like it was like a cleaner Philadelphia with a mid-west twist.  People seem a little more laid back and nicer there.  I currently live in New York which is the most industrial and bustling city i've been in.  Its a great city where you can find anything you want, but is so high energry it can exhaust you.  I just spend a weekend in Boston and absolutely loved it.  Boston seems high energy and young like New York, but lacks that abrasive edge.  I feel like I can be in downtown Boston and actually relax.  Its by far my favorite city so far.

What is your favorite US City?