From Emusicality.com...

I have listened to David Cook's debut single "Light On" and there is no doubt David Cook is along Chris Daughtry's line of music. David can surely rock the world -- just like any rock artist -- does with his unique and delightfully different voice. "Light On" is a song that every radio station will like to play all day. David Cook has shown his vocal prowess especially the part around the coda at 2:30.

Link: http://www.emusicality.com/2008/09/david-cook-light-on-sure-hit.html