Why Kellie Pickler? Because she has a decent voice, a cute bod and she's dumb and sweet. People in middle America love dumb people. Jessica Simpson, Bush, etc...

Let's analyze the rest of the competition and find out why they won't make it.

Ace Young - Good looks, bad voice. Girls like him but no one else does. No chance.
Bucky Covington - Bad looks, bad voice. Needs makeover bad! Teeth, hair, speech coach, the works. No chance
Chris Daughtry - Decent looks and a great voice. May win it all!
Elliott Yamin - Bad looks and an OK voice. Too ugly to win. Seems like a nice guy, though.
Taylor Hicks - Bad looks and an OK voice. Again, AI is girls voting. They're not voting for a guy who looks and dances like their dad.
Katherine McPhee - Good looks and a great voice. Not much of a personality and she hides her body. May be a good body but I don't know yet. I'd do her but I wouldn't vote for her.
Lisa Tucker - Cute looks and weak voice. Predictable. Boring. No chance.
Mandisa - C'mon, don't make me say it. She seems so sweet and nice that I won't make the obvious comments but she doesn't have a chance. This is a popularity contest and big girls don't win those.
Paris Bennett - Cute with a great voice but too short. Too short? Yes, that's exactly what I said. She'd win "dwarf idol".