Why: Time could turn this into quite a battle for the letter 'U,' but for now, the edge goes to Keith Urban. He's just been making hits longer than his closest competitor Carrie Underwood -- his resume is longer and his career more decorated. Both are still at the top of their professions and both are still turning out artistically sound and commercially successful albums. Underwood is slowly becoming every bit the live act as the 'American Idol' judge.

Honorable Mention: Carrie Underwood