I think Frodo is a hero, even though he fails at the end. There's no shame in being ultimately conquered by something much more powerful than oneself. That Frodo managed to get it so far, realizing that it was destroying him, is indeed heroic.

As for the rest, ITA. The story has many heroes, not just one. Sam may be my favorite, but I love them all.

BTW, while Billy Boyd doesn't do that much for me ordinarily, when he sang . . . whoo!