Pecan. I remember that I once took a personality test to determine what kind of pie I am, and the result I got was pecan, saying It fit me because it's sweet, but nutty. I don't know about that, but it made me want to have a bite of this kind a pie, because I hadn't eaten one before. So gave it a try, and fell madly in love.
I have always liked eating pecans, and had fond memories of going to pick them with my dad and aunt from the fruit trees at home. In a pie I think they add such a different and unique flavor that's rich and earthy, while still sweet from the filling, it just makes the sweetness more complex, instead of being all sugar and fruit. I like chocolate pies for this reason too, because it adds something dark just underneath.