Not been to every beautiful country out there... but the ones that I find phenomenally beautiful are (5) Italy (4) Switzerland (3) New Zealand (2) USA and (1) South Africa.
Italy is wonderful, though more for the culture and architecture than for amazing landscapes. Landscape wise it wouldn’t make my list - although some landscape exceptions are the Northern Italian Lake District around Como and Garda, some Mediterannean coastal areas, the Amalfi coast especially, and the Dolomites. Three of my favourite cities (Florence, Venice and Rome) are all in Italy and all are exceptionally beautiful from an architectural point of view.
Switzerland is gorgeous! I would say it's one of only two countries I've been where everything is beautiful! The North West around Basel is not stunning like so much of the rest of the country is, but even it is at the very least pretty. The Bernese Oberland near Bern (Interlaken, Lauterbrunnen Valley especially, Murren, Kleine Sheidegg) is probably my favourite thing in Europe for scenery. It's Alpine heaven.
New Zealand is gorgeous! Milford Sound, The Coromandel Peninsula, The Remarkables - are all remarkable! And with Switzerland it's the other country that I haven't seen anything unattractive in! Totally gorgeous, even if the weather is rather like the UK!
People are shocked when I say the USA is number 2, but it is seriously incredibly beautiful! Some of the most beautiful places I've been are there. These include Bryce Canyon, Yosemite, Glacier National park, Crater Lake, Grand Canyon, Zion Canyon, Big Sur, the Pacific Northwest etc! Of course a lot of it is quite boring but it has enough great places that it has to make the top 5 and I'd even say number 2!
South Africa is the most beautiful country in the world for me. Incredible. The variety of scenery is confusing in its sheer diversity! Obviously the variety of life is the most staggering thing - about 10% of all species of life on Earth occur there. The Kruger National Park, Blyde River Canyon, Cape Town (for me the most beautiful city on Earth), Garden Route, Cape Peninsula, Cape Winelands, Drakensburg mountains, Goldengate highlands park, Swartburg mountains, Wild Coast, Storms River Mouth, Waterburg, Kalahari desert (etc) are all amongst the most beautiful places I have ever been! The two most beautiful coastlines I've ever seen are both in South Africa and it's hard to pick between them. These are the coastlines around Cape Town and the Cape Peninsula, and the Wild Coast between the Eastern Cape and KwaZulu Natal. And there is so much to see in the country! It seems like an inexhaustible supply of beauty!
That’s my 50p worth at any rate...