I liked Air best as well for the same reason AJ. Kanon was ok (but I watched it while feverish so don't really remember that much about it), and I liked the first, comedy orientated season of Clannad, but After Story with all it's terrible emotional manipulation was nothing but rage inducing. Angel Beats isn't actually a Key property, but has a lot of the same writers behind it - it was fun until the ending ruined it all.
I don't really get on with shows that try way to hard to make me cry - Anohana is another prime example........god I hated that show.