Sheamus winning KOTR would be awesome, and a great way to conclude his 2nd year in the WWE. And as it's been said before, it would be the perfect way to bring the "King of Kings" Triple H back into the WWE going into 2011.
However, I feel that Sheamus is at a point in his career where he no longer needs to win KOTR to win another world championship, because we all know he'll have another reign under his belt by the end of next year. KOTR is sort of like MITB's older brother - it's the old-school way for WWE to push an up-and-coming mid-carder into the spotlight.
So for that, my personal picks are either John Morrison on Raw, or Alberto Del Rio on SmackDown. Daniel Bryan is US Champion, so he'll remain in that spot for a while. Big Zeke is a monster, but not main-event level yet. "Dashing" Cody Rhodes and Kofi Kingston are simply mid-card filler, etc.