Many I could name. The Cote d'Azur, mentioned in the original post is my pick for the most boring, overrated place in the world. Boring, stuck-up people, boring architecture, boring gravel beaches. Yet, go inland 20 miles and all is reversed.
My favorites are, in no particular order:
The National Parks of the United States
The Loire Valley
The wilderness of Nunavut
Spain- al of it
The Scottish Highlands
The Rhone Valley