I think Jazz topic is way too big. Way too difficult to list a must have CD list. Best way is to get some book ie. Stereophile Good Jazz CD guide, or Penguine guide, or some others. Then listend to style that you like and expand it from there.
Say you like Monk... he plays bop, post bop .. you may want to try some other album by him. Here are some of his best work (my opinion) Brilliant Corners, Thelonious with John Coltrane, Thelonious Monk and Sonny Rollins, Underground. Then you might pick those name who played with him such as John Coltrane or Sunny Rollins and goes from there ... we still in post bop, bop or hard bop ... well ..coltrane is pretty unique though.. then find something from Coltrane ie. A Love Supreme, Giant Steps, blue train. Rollins?? Saxophone Colossus. Then you may... try to see who is playing bop .. Dizzy Gillespee, Charlie Parker Now you get my point.
Once in a while you may want to jump to different style of jazz ... How about Cool, West coast, Free, Avantgarde??? Cool ... you may try Mile Davis "Kind of Blue" or Bill Evans "Sunday at village Vanguard"
In any case, you should have good book as reference. Another good book is All Music guide to Jazz. .. and one section of "Jazz Theory book"
Or www.nprjazz.org is a good site for sort of essential list.
You just have to be opened because jazz is really wide varieties of style.
These are some of my favorites that not mentioned too much in a list.
Keith Jarrette: Belonging, The Koln Concert
Don Pullen: New Beginnings or anything with George Adams
Patricia Barber: Nightclub
Rasann Kirk: Rip, Rig & Panic/Now please don't cry, beautiful Edith
Don Cherry: Art Deco
Um.. other than that ... more or less usual ... like other would probably recommend
