I've actually loaded these songs into ITunes and have them on my Ipod to listen to them. They're actually really good. I feel like they may not work as general background songs, but the line "The king has come unto his halls" could be played when Thorin hits level 10 and is crowned King of the Dwarves. Would really add gravity to the event.
And also, when an Ered Luin player with Thorin lands a killing blow on Smaug (when he's added), it could play "His foe is dead, the worm of dread". Not sure how easy it would be to program, but it would be cool.