I have the EXACT same problem. Although some folks in Memphis have told me that McNair is fine and will start (just some people, no one from the Titans or the NFL).
Dew Brees is in my Leagues FA pool and I am considering Trading Denver DT for him as a back-up, but I am not so sure I want to get rid of them. It would leave me with the Buccs as my only DT.
I say you and I both need to get another QB but the BIG question is who to get rid of.