hi guys,
can anyone tell me which country in Europe is the best place to live in and working in the field of science after Phd? :)

Sweden? Switzerland? Belgium? some other?

Probably no-one can really say, it rather depends on what you do and what you want from your life outside work as well. You could look up happiness measures or something if you like but to be honest that probably wouldn't help much either. What do you want from the country you live in? Why does it have to be Europe?