Jackie Chan, Jet Lee, Jeanclaude Van Dame these one of my fav because i love to watch spectacular fights
and Arnold Schwarzeneger for a part in Terminator2 
Seriously, these names aren't the ones you're looking for if you like fight scenes. there's one new name in town and it's Tony Jaa - Yes, he's really ugly and his acting isn't good, but he's certainly the best action hero around. Hey go pick up a copy of Ong Bak - you'll understand what i mean. I'm not thai, and i'm certainly not working under him, but seriously, he is that good.
I don't really have a favorite actor or actress cuz' there are so many of them, and they really put up fantastic performances all the time. Some people hate Tom Cruise, but i find that although he keeps playing the same kind of "I own - damn i'm going through a low - cool, i own again" role, he plays it well. but there are still some actors and actresses that are fantastic all the time.
Mizuno Miki, Abe Hiroshi, Watabe Atsuro, Yamada Takayuki, Nakama Yukie, Koyuki - ARGH that's all i can think of for now.
Western actors, well Tom Hanks, Jim Carrey (Kick ass performance in Man on the Moon and Truman Show), Funny that I can't think of any female actresses here...