Just FYI, this topic has been discussed numerous times in other threads. Do a search.

That said, in the developed world, I think Holland is far and away the best country for bicycles: especially Amsterdam; there are bicyclists everywhere, and very few autos

In the US, Portland is consistently rated the best city for bicycles, and it is richly deserved: The city has a comprehensive, integrated system of trails. Seattle (where I live) is very good as well, though our trails are more fragmented than in Portland.