Quests really shouldn't be in the mix. Because a quests is supposed to be in every rp. That's what a storyline is. Also a quest is something a person or a group of people strive to achieve, whether it be a giant heep of treasure, a legendary weapon, to be the best, to find a way out of some alternate deminsion, or even as simple as to find love.
Second of all I choose quests because it's the obvious answer, because an rp would truly be spam and/or boring something to achieve, some common goal (or it could be several seperate goals).
But if that wasn't in there. I'd have to go with Fantasy which I quess would be "others" because I'm a sucker for a good knights tale, or whatever the case may be! ^^