My top 10, in no particular order. Each has a substantial body of work and broke a lot of (enjoyable) ground during his/her career, which were elements of my criteria.
1. Joni 2. Pat Metheny 3. Van Morrison 4. Miles Davis 5. Bob Dylan 6. Duke Ellington 7. Neil Young 8. Muddy Waters 9. The Beatles 10. Dizzy Gillespie Honorable mentions are too numerous to name, led by Thelonious Monk, Hank Williams, and Billie Holiday, I think. The Beatles were the first artists I followed closely, single to single and album to album - which came our way at a good clip in those days. Prior to that, I was an 8-year old with my ear to Top 40 radio, soaking in the early rock and roll, pop, country, and even crossover jazz hits of the day (i.e. Stan Getz's collaboration with Jobim and the Gilbertos on "The Girl From Ipanema," Ramsey Lewis's take on "The In Crowd," etc.) I credit that smorgasbord - and The Beatles, for starters - for opening me up to eclectic tastes in my teens. As far as guilty pleasures are concerned, I was always a sucker for the novelty hits as a kid, things like "Itsy Bitsy Teeny Weeny Yellow Polka Dot Bikini" and "The Purple People Eater." Among my favorites were these singles which would excerpt other current hits of the day and splice in the key lyric at the appropriate time. Remember those? They were often set up as an interview, and the answers to the interviewers questions were the excerpts. Q: "What was he wearing?" A: "A white sport coat, and a pink carnation" (a Marty Robbins hit back in the day). Best, Jim