MASH - Alan Alda as Hawkeye, and David Ogden Stiers as Charles

Breaking Bad/Better Call Saul - Both Bryan Cranston and Bob Odenkirk did a great job in their respective leading roles.

Star Trek TNG - Patrick Stewart as Picard

Star Trek Voyager - Robert Picardo as the Doctor, and Jeri Ryan as Seven

Star Trek DS9 - So many from this cast, but especially Avery Brooks as Sisko, Armin Shimmerman as Quark, Rene Auberjonois as Odo, Andrew Robinson as Garak, and Marc Alaimo as Gul Dukat