I voted "The Gift." Many of the eps. listed were big tearjerkers for me, but "The Gift" is the only one that gets me choked up Every. Single. Time. No matter what. Buffy's determination to protect her sister against all logic, Spike's oath to protect her no matter what. And of course, Buffy realizing she needs to die to save Dawn. The gang's reaction to seeing her body . . . maybe it's just the music that goes with it (which is some of the best scoring in the whole series IMO), but at the end when the shot pushes in on Buffy's headstone and it says "She saved the world. A lot." Always, always, *always* makes me sob.