A good episode. I think Terry O'Quinn is a terrific actor. His acting, even down to his facial expressions are so realistic. I think he plays John Locke pretty well.
I agree. His character is very complicated - a "lonely old man" (Jack Shepard, LOST), and a seemingly pathetic one, but the tasks and responsibilty thrust upon him and his handling of these tasks say to me that there is way more to him than meets the eye. He walks the line between lonely old man and destined leader pretty well. You can't really help but to like him and feel for him, everything he's doing he truly believes is right. Jack and the others were so hard on him in yesterday's episode it almost made me upset - he's doing what he has to in order to save the only place he has ever been welcome. Beyond the character, O'Quinn does do a really great job representing this man, as you said his facial expressions and speech inflections are just about perfect.