I noticed a bunch of folks in the other thread add broccoli. Not sure if they are just trying to make it more healthy, or if they just like broccoli? I can tell you right now, I love broccoli, and cooked broccoli is certainly better with cheese sauce!
My old man used to make boxed mac-and-cheese or Noodle-Roni Fettucine with hot dogs (Fettucine Al Frankfurter), but he was culinarily challenged, having grown up in a family with 9 kids and in that brief era where cooking was "woman's work." Which means he likes dull, flavorless food that is easy as possible to create.
I, however, was raised more enlightened, and while my Mom always cooked to Dad's tastes, she made sure that we all could cook and encouraged us to experiment. Hence, I make my own mac-and cheese homemade, usually with colby-jack, monterey jack, or pepperjack cheese. Instead of a rué, I make my cheese sauce with heavy cream and cheese, usually with some garlic granules and pepper, although sometimes I add basil or cilantro as well. For additional flavor, I like to add peppers of varying heat (usually just bell peppers, though) as well as onions, and chunks of sausage. Sausage typically runs to polska kielbasa or summer sausage, although sometimes when feeling adventurous I will go with chorizo or even breakfast link sausage. I go heavy on the additions, as we often eat the dish as an entire meal, so heavy sausage and veggies, which makes it super rich.
Kinda like when you make homemade fettucine alfredo, you want more than just carbs and fat in there. Which gives me an idea, I could add shrimp or chicken as well as other vegetables to my mac-and-cheese. I can't believe I hadn't thought of that.