Johnny Cash is the fucking man, period. I did hear his music before the film came out, and I'm 23
Not trying to even begin to compare him to any other artist/band, but you might like Murder By Death:
http://www.myspace.com/murderbydeath
(They are not what you would think by the name...just took it from this movie -
http://en.wikipedia.org/wiki/Murder_By_Death)