Tomato sauce, then toppings like onion, mushrooms, peppers etc, a drizzle of olive oil then slices of mozzarella cheese and a scattering of italian herbs.
juggerling is correct...tomato is first (although i prefer garlic butter) followed by ham, pineapple, onion, peppers, mushrooms and sweetcorn followed by cheese, followed by lots of oregano and thyme.
Did you know that (according to Elizabeth David) the original pizza didn't have any cheese on at all ? It was a good way of using up left over dough and tomato sauce from the pasta dishes... Personally, I need mozzarella now and then. Oh, and I generally use those pasta sauces as the tomato base on my pizza... esp the spicy ones... lovely...
i made a chicago style pizza pie the other night which was odd - you make a bread dough then add ham then mozzarella and a thick tomato sauce - it was lovely tho!!