I think the secret to a good apple pie is all in the choice of apples. I like to use six apples in a pie–two granny smiths and then two firm apples of some hearty tasty stock and two mushy apples, possibly even one Delicious, which we know is the blandest apple in the apple world. That way you get juice and some falling apart action and a unique flavor every time.
Though, truth be told, I would eat a sour granny smith pie every day, too. Coupled with ice cream, there’s nothing better.