Tom,
I would tend to agree regarding Muirfield. While I love the quirk and charm of North Berwick and The Old Course, and the beauty and design of Dornoch, for me, Muirfield just presents the complete test of golf. It's hard to list a favorite because there is something great about each course that can't be found at any of the others. Maybe, it's my mindset because I'm used to playing competitive rounds, but Muifield just stood out to me. On another note, to me, there is nothing comparable to standing on the first tee of The Old Course and hitting that first shot and then returning down 18 for the finish. It's a magical place...probably my favorite "experience".