I saw this Financial Times article referenced by Rudy on Urban Onramps. Every year there are lists produced that rate the most "Livable Cities" in the world. I agree with this article that most of these cities are too expensive and boring to really live in.
"Our cities are our own – we make them inside us. No city means the same to two people so how on earth can we measure them?" Edwin Heathcote
I personally love Houston, even though people think it's an ugly city. There are no mountains or scenery, the weather is hot and humid, there is no zoning, etc. There are things about Houston that make it a livable city for me: diversity, opportunity, chaos and continuous change. All these thing might be just the reasons that someone else doesn't like it. These reasons are also exactly why I love the urban parts of cities more than the suburbs.
I also love Lagos, Mexico City and other "unlivable" cities. I happen to love the beauty of a city's ugliness, because people live there. People are beautiful.