Apparently the key will also provide users with a "wealth of goodies". As if Duke wasn't enough.
How many people are going to end up with a second copy of Borderlands just so they can say they've played Duke Nukem, then? To be fair, the Borderlands re-release includes all of the game's DLC. If you haven't played Gearbox's RPGShooter, now might be the right time to bite.