Fullmetal Alchemist: Brotherhood is amazing. I've only seen one episode so far, and now I love the whole series and think all of it is amazing. Why?
Because it has this song as it's opening theme.
Blooming excellent.
How important are opening themes to you? Has an opening theme ever made you love/hate a show before the episode has even begun?
Firefly is another example of this for me. Brilliant opening theme that set me up with great expectations for the episode.