Switzerland, Iceland, Norway, Ireland, Finland, Sweden, Faroe Islands, Portugal, Georgia, Croatia, Montenegro and Scotland and Wales (United Kingdom)
Hope these will help you out, good luck ;)
Never been there, the books and pictures I've gone through. Ireland, UK, France and Southern Germany. Oh, and Switzerland!
Slovenia is one of the most picturesque countries I have ever visited. It has it all - mountains, lakes, beaches, forests. Switzerland and Norway are worth mentioning too, but for more obvious reasons.
The Black Forest/Schwarzwald region of Germany:
https://www.google.com/search?q=schwarzw...
Provence in France:
https://www.google.com/search?q=provence...
Norway has lot of nature.
https://www.google.com/imghp?gws_rd=ssl