While not "bands", I would like to comment on a couple of great artists you've never heard of. The first is a singer/songwriter by the name of Andrew Newton from Northern Minnesota. He used to play (and maybe still does) small coffee houses and such. He would walk out barefoot with his guitar and a stool and play the most incredible music. He performed what I still consider THE definitive version of Leonard Cohen's, Hallelujah. He once played it right after a break during his set. People were still milling around and talking a bit when he started but by the second verse everyone was still and you could hear a pin drop except for his music. Talk about jaw dropping moments! I thought he would easily become famous but it never happened.
Another obscure artist, also from Northern Minnesota (there must be something in the water up there) is Arianne Lydon who is a very accomplished singer/songwriter. She has a sultry and interesting voice and is a virtuoso with stringed instruments. Have you ever seen someone play 12 string guitar and harp at the same time? Check out her tune "Fireflies" on you tube.