Canadian bacon or Green peppers or Batter fried eggplant
Ugh...so...batter fried eggplant probably is good, though the sauce and other items may play a role in that. I've never had it on a pizza before, and I know the other 2 are good (PEPPERS DO NOT KILL PIZZA!), so, while I feel bad voting against something I don't know intimately, it's the weakest option to me
Beef, onions, and green peppers or Sausage (good Italian sausage, not chain stuff) or Pepperoni
So, since the "good Italian sausage" was specified, Pepperoni is the weakest here by far. Unless you use turkey pepperoni or something, it can look unappetizingly greasy. It tastes fine (unless it's uber fatty), but the others also taste good, and have more robust flavour combinations
Pepperoni and mushrooms or Sundried tomatoes or Chicken and onions
Mushrooms are AWESOME, and I hate to vote against them, but pepperoni. Chicken with onions is awesome (I also love it with PEPPERS for the chicken cheesesteak thing). Sundried tomatoes are fantastic, as are regular diced tomatoes.
White pizza with pesto, shrimp, and tomatoes or Ricotta cheese + fresh garlic or Margherita (mozzerella, basil, and tomato)
Man, the first is good - I've had it before. But the other 2 are classic standby styles of pizza, and are awesomeness incarnate. Tough draw.