What is your all-time favorite main dish recipe?

We seem to frequently go back to this one:

Hot Taco Salad
Makes 8 servings

2 pounds ground beef
1 envelope taco seasoning mix
1/2 16-ounce bag tortilla chips (or Nacho Dorito's)
1 small onion chopped
1 medium tomato chopped
1/2 head lettuce chopped
Sauce
4 tablespoons butter
4 tablespoons flour
2 cups milk
1 pound velveta cheese

1. Brown Hamburger, drain, add taco seasoning mix and set aside.

2. Crush chips into the bottom of a 9x13 inch baking dish. Spread hamburger mixture over chips.

3. Layer onion, tomato and lettuce on top of hamburger.

4. In a large saucepan melt butter. Stir in flour and stir continuously until smooth. Stir in milk. Bring to a boil - stirring constantly and boil one minute. Add Velveta Cheese and stir until melted. Pour sauce over casserole.

5. Bake at 400 degrees for 10-15 minutes or until bubbly.