what type of discussion are you looking for? I'm used to white pie either being cheese and broccoli, or cheese and tomatoes. Personally, I like tomatoes with black pepper, basil, and garlic butter on top. Most shops that I've seen serving this type dot their pie with ricotta cheese. My wife doesn't like ricotta, so I use extra parmesan for flavor.
Some places do other types like chicken ranch, or cheese and shrimp.