In medium bowl, with mixer, blend sour cream, mayonnaise, cream cheese, cheddar cheese, chopped onion and green pepper, garlic powder, and black pepper. Crumble bacon into small pieces and add to mixture. Add chopped tomato and stir well. Garnish with shredded lettuce just before serving, if desired. Serve with Townhouse crackers or Wheat Thins. Also good served in a bread bowl with bread cubes to dip.