An impressive list. I would add The Lion in Winter (1968), featuring Peter O'Toole as Henry II and Katherine Hepburn as Eleanor of Aquitane. I love that film, especially the performance by O'Toole. The film also features young Anthony Hopkins as Richard (who'd become the Lion Hearted).

My wife and I just watched The Guns of Navarone, which is a very good movie with great actors, but we like Alistair McClean's other WWII story better, Where Eagles Dare, one of the rare films in which Clint Eastwood didn't get top billing. That went to Richard Burton.