"Martin Freeman made the Sherlock world real" to me. If the best acting is reacting, his John Watson is a master class.
Benedict Cumberbatch's Sherlock is mesmerizing and infinitely re-watchable. I think my dog has heard his voice third-most of all the people in the world :).
His Lincoln made me wonder, "was Lincoln really like that?"--which made me do my research, which made me realize "yes he was!"--which process enriched my life.