Probably a toss-up between the Galaxy from Star Wars and Middle Earth.
I like the idea of backpacking across middle-earth with a sword by my side, a pipe full of tobacco and the company of a few friends. Seeing all the great landmarks firsthand in between travelling from town to town sounds epic.
As for the Galaxy, who wouldn't want to pick up a wookiee companion and fix up an old ship so they can start their own trade coercing the crime lords for spice and supplies in some sleazy undercities across the Outer Rim. If I were lucky I might even be born force-sensitive, which, you know, would be awesome.