I lived in Spain for many years (due to work) and I regreted having to come back to the states. First and foremost their "social package" is lightyears ahead of the US. You get sick, you go to the doctor and get operated on without having to pay a friggin dime. As far as quality of life goes... the working hours there are from 9AM until 2PM and then from 4 to 7PM, with two hours in between to eat and take a siesta. Restaurants are a bit cheaper than here in the USA, and the quality of the food is lightyears ahead than what we have here in the US.
Salary-wise, it's pretty much even, although, because of the euro-dollar being so high, they now make a lot more money than I was making back in 2002. If you get laid off from your company your life is taken care of (by the government) for about 1 year until you get another job. If you can't find another job, they put you through school in order to learn something else. Gas is now about the same as in the US, although utility bills tend to be a bit higher. Education is better than in the US.
Et cetera.
Like I said, when I made the decision to come back to the states I regreted it eventually. I came back to a country ruled by CEOs, church people, etc. In Europe they are a lot more social than in the states. You can pretty much walk into any bar and talk about any subject you want and people will talk to you eloquently and politely (unless you're talking about US foreign policy which they now hate... intensely) tell you their opinion on the matter. Here in the states, you walk into a bar and tell someone about Darfur and how fucked up that part of the world is and if it's a man you're talking to the first thing he'll think is that you're gay trying to pick him up and secondly he'll tell you that he hasn't seen that Star Trek episode. Let's face it, we're a nation of dumbasses who get dumber every day.
The difference between smart and dumb is that when you're dumb, you have no idea you're getting dumber unless someone tells you, whereas smart people get smarter, and need noone else to remind him/her.
Oh, before I forget, they get 1 month of vacation, have about 3 times as many annual holidays than in the US and they basically ENJOY LIFE.