I have a few favorite combos when I'm fortunate enough to go to a place with many options:
1- housemade sausage w/lots of fennel, ricotta, mozz, and roasted red peppers
2- kalamata olives, red onions, feta, roma tomato slices, mozz, and pesto instead of tomato sauce
3- caramelized onions, shrimp, goat cheeze, and mozz
If I'm in the plain mood it's either pepperoni & green peppers or sausage & mushrooms.
Oh, and extra cheese too if I'm being especially indulgent.