i actually think its going to be David Archuleta. I think this season (and possibly all the other seasons) are obviously "set up" to have a specific contestant win. And David A is just the "type" that the producers are looking for. He's got the tween/teen audience as well as the older crowd (think Clay Aiken fans) and he's willing to do just about anything they ask him to do.
So, while I think David Cook SHOULD win, I think David A WILL win.
And thats probably best for David Cook. He's gonna be a superstar no matter what.
So, in summary.... I'm picking David A to win the whole thing.