Gary Oldman is one of my faves since he plays the bad guy chars with so much intense I love it (example in Leon the Pro)
Sylvester Stallone since he proved he can not only play the action hero but also can be quite funny dunno the movie names in English since in my country they change the names and they don't match the original ones.
Russle Crowe in movies like Master and Commander or Gladiator for instance he was great and also in the LA Confidential.
Klaus Wennemann you probably know him from Das Boot as L.I. he was a german actor and died early unfortuantely but he did great acting in a series called "Der Fahnder" and a couple of others.
David Rasche is immortal to be known as Sledge Hammer he was perfect for the role of a brutal yet in some ways helpless character who always tried to do the good thing in a very violent way.... superb.
Funny enough I can't recall a female actor at the moment, ah well.
EDIT
Right Katherine Hepburn was awesome and Gregory Peck was also one of my fave actors if we go back some time.