There is a Finnish (surprise
) metal band called Battlelore who reference to Tolkien a lot and even dress up as Elves, I think, but I know very little of them.
Aganzir could tell you more.
As for Nightwish, I used to like it a lot and I still think some of it is good. I don't like the newer stuff though, especially as I dislike the new (Swedish!
) singer. But then again, I never was familiar with their earliest stuff, which includes most of the ME references. Nightwish is very tolkienish in a way, though, I have never had problems with associating it to Middle-Earth, especially with all this stuff about longing for the sea/ocean.