I loved watching Jack Elam. Anybody remember the F-Troop episode where he played the notorious gunfighter Sam Urp?
L.Q. Jones... man, he's been in so many westerns, TV shows and movies, very few know him by name. He was a bad guy in Hang 'Em High, one of my favorites.
And speaking of Hang 'Em High, another bad guy was Bob Steele, who also played Trooper Duffy on F Troop. He was in dozens of TV westerns and was in B movie westerns all the way back to the silent era.
Strother Martin was another great bad guy.