Man, my head hurts from the BTTF-like temporal paradoxes. Two John Lockes in the same scene! Equally jarring was switching from '77 to '07 and seeing the eternally youthful Richard interacting with both groups, with the '07 Richard alluding to things that, from his perspective, have already come to pass... and yet still may not! Just the kind of thing that makes your head spin, but it's still damn fine television!
I was wondering how much longer it would be before Sayid showed up. Kate really sold that scene, 'cause she had me believing... if only for a split second... that she might've been shot through the back. That was a close one.