This is going to sound a little bizarre, but here's a wild card name to throw out there: Drew Bledsoe...
After the magical 2001 ride, it was pretty evident that Brady >>> Bledsoe, but this was still the man with a $100 million arm, and he was going to a divisional rival?? I dreaded those two Bills games in 2002 (which, of course, the Pats won handily). New England pretty much owned Drew through 2004 (save the Lawyer Milloy bowl, of course), but at the time of that trade, I wished he had gone anywhere but Buffalo.