From The New York Times:
Powers Boothe, Actor Known for ‘Deadwood’ and Other Dark Roles, Dies at 68

Powers Boothe came to my attention a couple years ago.  When I was watching Deadwood, I noticed that the Cy Tolliver character looked familiar.  I googled the actors name, and discovered that the reason I recognized him was because he had also been in Hatfields and McCoys, which I had seen the same year.
Actually according to his Wikipedia bio, he's actually been in a ton of stuff I've seen.  Most of which I don't even remember seeing him in.  (For example, apparently he was in The Avengers, but I don't remember the character.)
I do, however, remember his memorable performances as Curly Bill Brocius in Tombstone and Alexander Haig in Nixon.