There are not too many people who will argue that the first season of Lost contained some fairly exceptional stories. Even the second season was pretty good. The third season, however, really started to fall off. Until now. It is quite possible that because the last twenty or so episodes just haven't been very good it made this episode stand out. It is also possible that this episode was just that good.
Whatever the case, this is some of the best that has come forth in quite a while from the Lost crew, and it is good to see them getting back on track.