That's an easy choice for me (assuming each singer at her prime)...
Going on looks and vocals:
Debby Harry - had bedroom eyes, sounded mostly sober with just a hint of punk
Stevie Nicks - looked like she's was wearing bed sheets, sounded stoned with a trademark nasal voice
Janis Joplin - always had that next morning bed hair look, sounded drunk and belted it out
So I guess I'd go with......
Linda Ronsdat - innocent look but gifted with a phenomenal vocal range for a rock/folk singer
Truth be told, I'm a huge fan of each of them. In fact here's Janis and I hangin out in NY...
View attachment 3507783
(...at the Wax Museum)