A co-worker of mine gave me her mac and cheese recipe - hers has been the only homemade version that I have ever liked in my life. My rendition turned out pretty close to hers so I consider it a success.
Start by cooking your macaroni - I used half of a 900g package (only part of which is pictured below). Salt it well. Shred a variety of cheese - probably about 2 cups (I used regular and sharp cheddars, while my co-worker used pepper jack and cheddar).
In a 4-cup measuring cup, melt 1/4 cup butter or margarine and add 3-4 tsp of flour to make a thick slurry. Add 1 1/4 cup of milk, and either cube 1 1/2 cups of Velveeta or add about 1 1.2 cups of cheese whiz. Melt the mixture in the microwave and stir every minute or so. Add more cheese whiz or flour if it's too thin, or milk if it's too thick. It should be just thin enough to pour onto the macaroni.
Grease the casserole dish very well (Pam or margarine or whatever you prefer) and add half of the macaroni. Sprinkle half of the cheese on top, then layer with the next half of cooked macaroni. Pour the cheese whiz mixture over the entire dish evenly, then sprinkle the remaining cheese on top. Add salt and pepper and paprika for colour.
Bake at 425 degrees for about 25 minutes - until the cheese on top is thickly crusted and nearly burnt. Serve with more carbs if desired (I can't resist carbs so I paired it with cornbread). Enjoy!