[Most important quests?]

That's wonderful, thank you.  Especially for the info about the Ancaria Airlines quests, now I don't have to feel I'm missing out by playing a Shadow character. 

[Most important quests?]

I know of three quests, the "Blind Guardian" quests to unlock the concert video, "Feed The Poor" to gain extra skill points (although I wish there was a Shadow version for the Inquisitor) and the "Unique Mounts" quest to unlock special mounts.

Are there any other quests that are considered "must-do's" for all players?