1. Hogwarts School of Wizardry and Witchcraft (Harry Potter, J.K. Rowling)
2. Naboo and Bajor (Star Trek, Star Wars)
I'm cheating a bit here because both settings primarily appear in movies (though book settings have also touched on them). I lump them together because they're...similar in many respects. Compare, for instance, their respective architecture. Culturally, they both blend high-technology and rustic simplicity. Despite their obvious technological potency, the cities of both planets still maintain a charming medieval-to-Renaissance appearance.
Also, I'm intrigued by the idea of a planet that elects adolescent girls to govern it.
3. Riverdale (Archie Comics)
Riverdale is the city I always wanted to grow up in. Archie's neighborhood has that cozy surburban look -- sidewalks and picket fences -- but Pop Tate's malt shop is evidently only blocks away, as are ballparks and most of the city except for downtown. It has mountains, beaches, a lake, and a river. Related: whatever town Henry and Beezus (Beverly Clearly) lived in, for the same reason.
4. Palo City, California (California Diaries)
I suppose this is mostly a case of wanting to live where characters I liked so much lived, though Palo City has high points of its own -- a lovely park with rock-climbing opportunities, and Venice Beach is only two hours away. In my younger days I used to comb through a map of California looking for the city (working within a radius of Venice Beach) before realizing it as fictional. I did manage to move there in one way, though -- whenever websites ask for my location, I happily respond...'Palo City, CA'.
5. Terminus/Foundation (Foundation series, Isaac Asimov)
It's a city founded by scientist-librarians who are destined to rule the universe. I don't much care for the neighbors, so let's move there after the Four Kingdoms have been defeated, eh?
6. The Shire, J.R.R. Tolkien
I've never finished the Ring trilogy, but the lack-back feel of the Shire
7. Lake Woebegone
Where the women are strong, the men are good-lucking, and all the children are above average. While this is technically a town that began in a radio/variety show, Garrison Keiller has written books set in Woebegone.
8. The Boxcar in the Woods (Gertrude Chandler-Warner)
9. Andalite Home (Animorphs)
I want to see the place that gave birth to the Andalites, They're sort of like elves in that they're very much in-tune with nature, but snobbish. Warrior-scientists, the warrior class can 'acquire' the DNA of any animal and then morph into it. They ingest food through their hooves, and communicate with one another via thought-speak. Intelligent and powerful, they'd be magnificent aliens were it not for their cold-blooded policies when it comes to defeating the galactic-empire-building Yeerks -- which sometimes involves writing off and leveling whole planets taken by the Yeerks because that's easier than fighting for their reclamation.
10. Clanton, Mississippi (A Time to Kill, The Summons, The Last Juror, Ford County, John Grisham)
Clanton Mississippi is a fictional town in equally fictional Ford County, Mississippi. Although urban sprawl has diminished its charm, somewhat, it still manages to hold on to some of that southern-small town idyll, especially downtown -- amid the grand old Victorian homes obscured by Spanish moss and the courtyard square. While the picturesque descriptions of it compel my attention, its colorful characters back the town especially visit-worthy.