What type of quests do you prefer?

[Altanas]

I like quest chains that have a story.
Kill quests can be ok, if it's something beyond: .... kill 15 undead

Agree, the problem with loads of trash mob kill quests is usually often the action is already over and you have to report back to an npc for completion. I think SWTOR for example while using kill quests at least mixed it up in their daily "heroic" kill quests some of which did take 20min if done at the recommended level, and would require a party.