In a medium mixing bowl, blend together the cream cheese, sour cream, mayonnaise, and ranch seasoning until smooth.
Spread the mixture evenly into a shallow serving dish.
Sprinkle shredded cheddar cheese over the top.
Add a generous layer of crumbled bacon, followed by the chopped lettuce and diced tomatoes.
Garnish with green onions if you like.
Serve chilled with crackers, chips, or sliced bread.