Someone mentioned Bruce Gradkowski earlier. Bruce is a nice quarterback and will probably do very well in the league at some point, but he's a bad fit for the offense the Dolphins run. As with any position, the Dolphins have critical factors they look at relative to the quarterback position. One of the things that stands out as a critical factor is a strong arm. Gradkowski doesn't really have a downfield passing attack type of arm. I think he will fit in very well with a team that runs a west coast style though.
Now, Charlie Whitehurst has at least three of the critical factors that the Dolphins are looking at. He's got the size they want, the arm strength, and the mobility. The question about Whitehurst has always been whether or not it will finally click with him. I think he's potentially a great fit for the Dolphins offense. The only quarterback that would probably be a better fit is Jay Cutler.