Chances are good we’ll be seeing 50 Cent in a group situation from now on. Today begins the retail race between the Kevlar kingpin and his Soundscan nemesis, Kanye West. By now you know about the challenge. Fiddy says he’ll retire from being a solo artist if West’s Graduation outsells Mr. Cent’s Curtis in the next seven days. Whose fans are willing to pony up? Which CD is more fun to listen to? We smell rap’s second biggest money-maker looking at a future of passing the mic if he lives up to his promise. Weigh in below.