User blog comment:JCEHunter/BL or BL2 Soundtrack.../@comment-1927317-20100803053236

I doubt they would include any more non-original music than they have in the first Borderlands. Getting permission to use tunes like that takes money that will likely not pay for itself. No one is going to see that Metallica is on the soundtrack and suddenly say "I MUST have this game!"

Besides, original content is the spice of any game. I like to know what kind of feeling Gearbox is conveying by the music they write for a given situation, not just copy/pasting someone else's tunes and cheaping out.