Tori Amos. She dresses herself down a lot on purpose, but she's incredibly sexy if not 'hot'. Her musical talents are unbelievable as well.
Ann and Nancy. I could find better pictures of each, but this will do just fine. Might not be hot now, but when I was 8-18...
And Ann's voice is incredible. Watch Nancy playing Crazy On You in the 70's.....HOT!