If we are talking beautiful as in the nature, IMHO Venezuela is a good choice. It has amazing variety: beautiful Caribbean islands (Los Roques) and beaches on the north coast, the Andes mountains in the west, Amazon jungle in the south, the world's highest waterfall, flat plains (Grand Sabana) and the Orinoco delta. All in a country approx. the same size as France.
I'm from Australia, and lived in British Columbia, Canada for 2 years. Both are amazing places, BC is so green and lush, whilst you still get the amazing white winters. The weather can be dreary in winter though, if it's not snowing. Australia is lush in a different way (At least on the east coast). Green, warm, vast. I love it. Australia all the way! Woohoo!
Mine most definitely; Kenya, with all the world-life (national reserve as you leave JKIA Airport), forests (ones which are still standing), roads tarmacked and earth beaten ones, diverse culture (42 tribes), Matatu craze, suburbs and slums thriving side by side, nothing beats Kenya
I think the most beautiful country, is Indonesia which has many island charm just for a vacation and recreation.haha!