To kick things off, I'll go with the first jazz album I ever bought, the first for many. There are more copies of Miles' Kind Of Blue in circulation than any other jazz record so you can pick up a copy for maybe $5. If you are unfamiliar with the record, it is absolutely necessary that you check it out. Released in 1959, at the pinnacle of jazz, it features modal compositions that Miles wrote in the cab on the way to the studio. His sextet at the time included John Coltrane on tenor, Cannonball Adderley on alto, Bill Evans or Wynton Kelly on keys, Paul Chambers on bass and Jimmy Cobb on drums. Instead of using then-tired ii V's (the most common chord progression in jazz) Miles wrote modally (using scales begun on notes other than 1) to generate entirely new improvisations from his sidemen.
For those who play instruments, Kind Of Blue is a wealth of language, and it wouldn't hurt to transcribe every solo note for note. Folks who don't dig jazz, check out this record and tell me what you think - most importantly, though, LISTEN.
Let me know if you can dig.