not particularly big on 'zomg where were you when' threads (was working in a restaurant, coworker got a call about it, we turned on the tv), but a related story of note is a year or two before a friend and i visited the towers. we were going to go up to the viewing deck, but there was a really long line, so we figured we would come back some other time, because hey, wheres it gonna go? oops.
also, i remember standing next to it and looking up and thinking that it didnt look so tall. but then, i AM 6'5"...