Day 18 in the 29 Faces Challenge, but I have considerably more faces than that. Not counting the older faces, nor doubles in a single work, there are now... 29? Really? Did I count that right? Anyway, this is possibly the 29th, but at least, the most recent.
Professor and Headmaster of Hogwarts, Albus Dumbledore:
Atop the Astronomy Tower, Dumbledore sees Draco Malfoy approaching. We all know what Draco has in mind, even Dumbledore, but he politely asks, "Good evening, Draco. What brings you here, on this fine, spring evening?" Polite, but wary. He knows this must be handled perfectly, for his own plans to work out -- for the greater good.
This is the second actor to play Dumbledore, Michael Gambon. His portrayal of the character is rather weak when he takes over the job in the third movie, from the late Richard Harris. Perhaps he was directed that way. This later Dumbledore requires a good deal of dynamism, and Gambon is fully up to the job. He is the forceful wizard that ties together so many elements of the story. In the last book and movie, we finally get to understand who Albus Dumbledore really is.
And an older pic:
"Scabbers" --> Peter Pettigrew, from HPPoA.