Clannad was a really good anime. I'm rewatching After Story now, and found that the only arc I didn't like was
I think that if After Story was 12 episodes like Refrain was, it would have been much better.
@Optic: Angel Beats has a different producer than Clannad. Also, Clannad will have a different feel than Angel Beats as it was adapted from a VN where Angel Beats is an anime that will be getting a VN adaption.