Some of my favorite areas from FFXI include the Horutoto Ruins, Ro'Maeve (+Hall of the gods), Pso'xja, Caedarva Mire, and of course... The Boyahda tree.

I really like to see ruins of previous civilizations, as you can note from some of the zones I like the most. I really find the lore of video games to be fascinating, and being able to explore areas of... historical significance(?) in games such as FFXI were really enjoyable. I think Pso'xja takes the cake for me as far as that goes.

With all of the lore we have gotten recently in FFXIV, thanks in large part to the Monk quest giver, it would really be cool to see some ruins of these long-gone civilizations, particularly the Allagan Empire.