In "The Two-Horse Job", when Eliot and his old flame get back together, the backing track is a song by Kane's band called "More Than I Deserve". Why license when you have the actor working for you anyway?
And then there's "Thinking of You", Eliot's song from "The Studio Job", which Christian Kane wrote and sang himself. He's actually a professional country music singer as well as an actor.
The violin solo in "The Scheherazade Job."
To elaborate, it is sobeautiful that it stops the others dead in the middle of their job and makes Parker shed a Single Tear.