Claude Rains! So talented an actor, but so overlooked and under-loved, in my own humble opinion. While not really a "leading man" type of actor, his supporting performances in movies such as "Now Voyager", "Mr. Smith Goes to Washington" and "Casablanca" are flawless and inspired.
Also, I wouldn't complain about a month devoted to Peter Lorre, another amazing actor who probably doesn't get all the acclaim he deserves.