Kanto. For sure.
Depends on what you're talking about specifically since I have yet to experience it for myself. (HG/SS that is; not the originals) I'll have to keep this in mind during my playthrough.
The battle themes, overworld themes, etc.
Kanto has better music, but it's so depressing. Everything is changed for the worse from FireRed/Leaf Green.
I haven't goten to Kanto in HG yet, but from experience with both regions in other games, I prefer Johto.
Quote from: Missingno6 on March 28, 2010, 07:06:28 PM
The battle themes, overworld themes, etc.
Music, basically?
I like Kanto's better, although Johto has so many more things to do that can take show you that music.
Battle Frontier uses Johto trainer battle music, Elite Four uses the Johto gym battle music, even the Safari Zone and Bug Catching Contest use the Johto wild battle music. Nothing in Kanto is significantly repeatable aside from just wandering into a patch of grass. Even so, Kanto's major reductions (Mt. Moon, Pokemon Tower, Silph Co, Pokemon Mansion, Celadon Underground) give even less opportunity to hear it.
Though that was mainly directed at battle music, I believe the same applies to overworld music as well. My only complaint about the Kanto music is that the GB Player doesn't give music from Red/Blue, but instead, from Gold/Silver (or if the song wasn't in G/S then it has a newly-remixed song made in 8-bit style)