There's ton's of music that helps me through all times, but only a few artists, composers and songs will make me stop and focus on the music. A short list:

Canon in D Major - I prefer the symphony, although I've heard it by banjos, and was enthralled.

Pink Floyd - "Dark Side of the Moon" is my favorite.

Joni Mitchell - "Court and Spark" is my favorite.

Rikkie Lee Jones - "Pirates"

The Dregs - Originally the Dixie Dregs. Obscure and only instrumental.

"Honky Chateau" by Elton John.

"Abbey Road" by the Beatles.

The Allman Brothers