I think McCown should get some playtome this season for sure. If we draft a rookie you can kiss 2007 goodbye, and that might be all the time Gruden has. Might be better for the Buccs if Gruden was fired and a new guy could come in and build an O around Simms.
Personally, I'd rather spend whatever money would be going to keeping Chris Simms and throw it at somebody that can make plays on Defense -- pick a position, there is no place on the defensive 11, other than maybe Ronde, that couldn't stand to be upgraded.
Chris and Bruce share one thing in common -- both showed/have shown "flashes" of being something more than they currently are. I don't know that two of them equals one whole QB. Pick one and move on -- possibly bringing in a steady veteran hand if things break down.