Help me build up a jazz album collection. Can you suggest a must have album?

Check out YouTube. There are many outstanding videos that cover your inquiry of essential jazz records. Listen to the suggestions and then purchase what you like.

Umbrella label - Boss Brass - Rob McConnell - big band jazz D2D - incredible sound

Guitar - Ed Bickert, Emily Remler, Pat Metheny, Grant Green

Piano - Oscar Peterson, Bill Evans, Sonny Clark

Blues? Gary Moore

Trumpet - Chet Baker, Miles, Harry Edison

One thing I do - you are listening to an album, and maybe you like the piano - check who is playing; Miles was great about picking new players in his bands.

Sax - Sonny Rollins, Stan Getz, Paul Desmond

Have Fun!!

Forgot 

Sheffield Labs - great D2D label - Harry James big band, among others

Jazz at the Pawnshop - old album, great music and sound

Gary Moore, fine guitar player with unique style. Very emotional, very open.

For Bill Evans, I like Waltz for Debbie even more than the Village Vanguard album which came from the same series of performances.  Also, his Portrait in Jazz.

I concur otherwise with many of the above suggestions.  But an omission is Herbie Hancock--get a greatest hits anthology or Maiden Voyage and (if you like electric funk-jazz) Chameleon.

Paul Desmond is my favorite alto-sax player.  His albums with guitarist Jim Hall are wonderful, although one of them had some string arrangements I could do without. Easy Living is one of their better albums.