Xbox wins this one easily and honestly DC is mostly nostalgia dust by now. Yes, it had some amazing games in a short time span, but the Xbox had a bigger impact on the industry and managed to gather a far better gaming library. While most every major Xbox exclusive is still highly playable today, I would only go back to games like Power Stone and Crazy Taxi (Maybe a bit of JSR) on the DC. I'm sorry, I know that the DC was a great machine and the last great "hurrah" from Sega but the Xbox managed to outlive and outclass it on every front.
Vote the Mayor for Mayor!