DRK is my favorite one, for a bunch of reasons already listed up there. I remember it taking me by surprise the first time around (30-50), cause I never expected the warrior of light to get... you know, characterization of some kind.

That said, the WHM quest in 5.0 pulled at my nostalgia strings with its simple "where are they now?" story. The job quest itself was plain and absolutely nothing to write home about, but I started as a conjurer back in 2.0 and doing that WHM quest felt like going back home after years of being away. It's funny, cause I'd gone back to South Shroud several times before in the past few years (mostly to enter Palace of the Dead or take pictures in the forest) but I never really felt like I returned... until the latest quest. I feel like I gained a renewed appreciation for traveling these old roads on foot, or mount, rather. Flight is a great convenience to have, but conveniences have rarely ever led to memorable moments for me.

Standing there, next to Raya-o and those detestable moogles, I remembered the simpler times when the game felt fresh to me. I still very much enjoy FFXIV, but that spirit of "newness" can't be recaptured.