The political and social climate is best in Scandinavia, I suggest Norway in particular. Germany has a very stable and sound economy, with a rather secure labour market. Luxembourg has one of the highest salary levels in the world. Switzerland runs according to a unique democratic system where you have referendums in all important issues. The UK has the advantage of using the English language, which means you won't have to learn a new one. It depends on what you're looking for, really. Personally, I would definetly go with Norway. Seeing as you're from the US, however, it might feel a little too rural for you.
Places to avoid: The Balkans, Italy, the Baltic states and most of eastern Europe... And Spain, to some extent. Their economy is on the verge of collapse, and politically as well as economically they're still trying to make up for 35 years of fascist dictatorship.
The only downsides I can see with Norway are that it's very rural, and that they speak norwegian. It's a terribly ugly language. Other than that, they've got a very admirable political system, a very sound economy, a great social security net, very high salaries and overall a high quality of life.
Edit: As a general rule... The further north in Europe you go, the better it gets.