Room 888 at the Plaza Athenee for me (an Eiffel suite). Had booked a deluxe junior suite and was massively upgraded - As always, booked through DavidO. This was certainly the nicest room I have ever stayed in, and the huge upgrade was the perfect xmas present for me on our stay there over the holidays.
After that, I would say mu suite at the Riad el Fenn, mostly for the bathroom.