I would have to say my favorite country I've visited is Costa Rica. With its jungles, cloud forests, volcanos, rivers, hills and spectacular beaches, its a nature lover's paradise. Unlike most of its neighboring countries, its has a stable economy with VERY friendly people and hardly any crime. The food is excellent, the women are beautiful, and the weather is just about perfect. Pura vida!
My favorite single place, though, has to be Amsterdam. Enough said about that.