Hmm, all of the above!

Seriously, a good quest
does have all of the above. It starts with an excellent story; there has to be a good reason why the PC should accept a certain quest. Make the story intriguing, not simply another FedEx quest. Twists and turns are greatly welcome! Stuff like that is what makes a gamer actually feel like he/she is part of the game.
Adding new areas, rather than recycling old ones, is always a big plus. It is especially uplifting to veteran
BG gamers who have "seen it" and "done it all." Area deja vu is not good, but if you could somehow use the notion of deja vu and weave it into a good storyline, then that would be cool! For example, PC saying to him/herself, "I had a strange case of deja vu today. I envisioned myself being hunted by a creature...again. A creature not of this world, but of what world, I am unsure. The creature's face I could not discern, but it was relentless in chasing me. I barely escaped, just like the first time I imagined this."
So, uhh, yeah, I guess I went back to the story aspect, which is vital!

Adding various choices and outcomes are exceptionally good as well.
Characters are important too. I should rephrase that...characters with
personalities are important. Think about all the
NPC's in
BG1 and
BG2, if you met them in person, wouldn't you feel like you knew them already? They make lasting impressions in our minds, and a good quest will have such characters in it. Make the characters come alive through their written dialogue and voice acting.
A handsome reward at the end of a grueling quest is most appreciated as well. Personally, I prefer finding enchanted items rather than gold or gems. Although, a little of both isn't bad.
Edited by TheWizard, 13 August 2005 - 10:08 PM.