Lemon, with homemade whipped cream if possible rather than meringue (I like meringue, but it tends to slide/melt off the pie and a nice creamy top is just easier).
My mother made amazing fruit pies back in the day. Blueberry would have been my favorite but her cherry pie would be a very close second. I recently tried Key Lime pie for the first time and really enjoyed it. I think that might be 3rd.
I will eat it, but Pecan pie is really off the deep end on sugar content.
Sort of like my mother in law's favorite Marie Calendar Pie, Chocolate Silk. Sooooooooooooooooooooooooooooo salty!