I like Marianne Faithfull, but I find her work to be a bit uneven. Some of it interests me and a lot of it just doesn't do anything for me musically. Broken English is my favorite album by her. It contains my all-time favorite cover of "Working Class Hero" by John Lennon and the entire album is interesting enough to hold my attention. All of the other albums I've heard of hers, just have an occasional song or two that I like and the rest just seems like filler to me. She's one of the best live acts I've ever seen, though. Her music and vocals sound much more enjoyable and powerful live than on record.
She also sings my favorite version of "Sister Morphine"
Marianne faithfull - Sister morphine - YouTube