In an article entitled What The Bard and Lear Can Tell A Leader About Yes Men, the Washington Post compares Lear to Bush on the whole question of surrounding yourself with die-hard loyalists who will only tell you what you want to hear.
I'm not sure I fully agree with the comparison, as I really do believe that Bush surrounds himself with truly loyal people, regardless of competence. That's not the same as the feigned loyalty of Regan and Goneril who say whatever it takes to get what they want, and then change their tune as soon as they have it.
I do agree, however, about the "hurt himself by shutting out those with a dissenting opinion" line. That's certainly true.