What a great idea.  Thanks Mark.  I look forward to reading all the lists. 

Here's mine, by genre:

Progressive Metal/Death Metal 

1.  Porcupine Tree -- In Absentia  [also Deadwing and Fear of a Blank Planet]

2.  Opeth -- Blackwater Park  

World Music/Andalusian/Middle Eastern 

3.  Al Andalus -- 21 Strings  [performed by Julia and Tarik Banzi, my first guitar teacher and her husband, and Charlie Bisharat, violinist extraordinaire.  An absolutely wonderful album with a universal appeal.]

Modern Jazz 

4.  Pat Metheny, Lyle Mays -- As Falls Wichita So Falls Wichita Falls

5.  Michel Petricciani -- 100 Hearts  [passed away a few years ago, may he rest in peace]

Modern Flamenco Guitar

6.  Vicente Amigo --  De Mi Corazon Al Aire

7.  Paco de Lucia --  Siroco  [Paco basically invented modern flamenco guitar]

8.  Gerardo Nunez -- Jucal  [unbelievable technique, and a great teacher] 

Traditional Flamenco 

9.  Agujetas -- En La Solea  [flamenco singing is an acquired taste, but it doesn't get any better than this]

Sacred 

10.  Arvo Part -- De Profundis, performed by Theater of Voices

11.  Karol Szymanowski -- Stabat Mater, performed by Simon Rattle and the City of Birmingham Symphony Orchestra

 12.  Monteverdi -- Vespers of the Blessed Virgin, John Eliot Gardiner et al.  [The music is great and the quality of the recording is spectacular.]

Classical/Symphonic 

13.  Wanda Landowska, harpsichordist -- anything performed by her

14.  Sviatoslav Richter, pianist -- anything performed by him

15.   Stravinsky -- Rite of Spring, Leonard Bernstein & London Symphony Orchestra