Leonard Cohen's songs are awesome to listen to. His talents as a musician and writer are apparent in any of his songs. In my opinion, there isn't a bad one in the bunch. I'm no musical expert, but I don't think there could have been an improvement on any of his songs. His music is not without religious influence, but I'm hard-pressed to determine what kind of religious message he's trying to convey.
I first heard Leonard Cohen's music on "Pump up the volume", a movie starring Christian Slater about a high-school student running a pirate radio station. In a couple of the scenes of the movie, Slater's character plays some of Leonard Cohen's songs, including "If it be your will."
His songs have also been used in popular movies like Shrek, which features "Hallelujah," sang by someone else.