BUFFY THE VAMPIRE SLAYER:
Season 5 Finale, Season 7 Finale
(The fifth season ended with an amazing epic battle, and overwhelmingly emotional punch to the gut) (Season 7 finale was just everything you wanted. Main characters died, epic, I mean EPIC battle, and great emotions all over the place)
LOST:
Season 1, 2, 3 Finales
(The first three seasons ended with some of the best finales ever in television. Suspense, emotion, mystery.)
DEXTER:
Season 4 Finale
(After that amazing last kill of the season, and that shucking and powerful final scene, this was a top game episode.)
BREAKING BAD:
Season 4 Finale
(After an amazing season, the suspense, the brilliant acting, writing and directing was just at BEST of in that episode.What an epic way for Gus to go.)
GAME OF THRONES:
Season 1 Finale
(You watched the episode? If you did, then I need not explaining.)
SCRUBS:
Season 8 Finale
(After an 8 year ride with this characters, to see the future, in this one brilliant scene, is just enough to get me tear-eyed. The Book of Love.)
ANGEL:
Season 5 Finale
(I was was ultimately entertained by that episode, but pissed of it. Great way to end a season...IF YOU HAVE MORE SEASONS TO COME!)
I'm sure that there is a lot more, but for now this are the ones I can think of.