Done listening to Madonna's discography and this is the ranking I've come up with:
Bedtime Stories
American Life
Confessions
Ray of light
Music
Erotica
Like a prayer
Like a virgin
S/T
Hard Candy
Rebel Heart
True Blue
MDNA
Overall I'd give her discography a 4/10. Maybe a 5 if influence is taken into consideration.
None of her albums really appealed to me and I only kept like 10 tracks total on ITunes which I really liked.
American Life is her best song imo in all its trashy and self-indulgent glory.