Its very interesting to see people in each region perceives the other regions. I'm a brazilian, and wouldn't imagine that US has so few good places to live.
All of the good places to live in the USA are balls-expensive, because there aren't very many of them.
The Upper Midwest (Chicago, Madison, Minneapolis, Ann Arbor) is great if you can get an interesting job there. The weather isn't as bad as it sounds and the cities themselves are beautiful (although I wouldn't recommend most of the suburbs).
Ann Arbor has absolutely no nightlife that doesn't involve young kids and drinking too much. Chicago's bar and club scene is full of the hyper-douches that (for the most part) weren't smart enough to make it to the coasts. And almost every major urban center in the US requires a car to live.
I grew up in Detroit and spent a lot of time traveling and working around the midwest, and those kinds of places are exactly what I envision when I think of unlivable American cities. They simply don't have the density to support the kind of scenes that make living in a city fun. Chicago is borderline, but the car thing and the snow thing totally ruin it. The parts of the city that are close to anything fun are expensive to live in.
Fact is, any state with a default 2AM bar/club time is at a severe disadvantage.
I think the list for the US at the moment is NYC, SF, and perhaps maybe Seattle or Portland - but I haven't been to the northwest so I can't comment directly.
Chicago's bar and club scene is full of the hyper-douches that (for the most part) weren't smart enough to make it to the coasts.
There's a lot more to Chicago, and if that's your take on it you obviously haven't spent much time here. It has an incredibly diverse and vibrant nightlife.
Also, the notion that if you live in Chicago it's because you weren't "smart enough to make it to the coasts" is incredibly insulting and narrow-minded.
I'm with you on "the snow thing" but every other critique makes it sound like your definition of a livable city is one in which you and your friends can reliably get hammered every night.
The rest of the bay area is car land. Especially the peninsula where most of silicon valley is concentrated. I tried living in the peninsula on a bike for 5 months, wasn't so nice.
You have a funny definition of "isn't as bad as it sounds." I live in Indianapolis and that's about as close to Chicago and all points north as I wish to go during the winter.
All of the good places to live in the USA are balls-expensive, because there aren't very many of them.
Berlin's great this time of year.