I usually just take any recipe with good reviews and modify it to suit my tastes. The last batch I made had leeks, pancetta, and a very sharp cheddar from Trader Joe's.
Don't forget a bit of nutmeg-- 10 times better with it than without it.
I definitely make mac and cheese by the seat of my pants. You just need to make a bechamel, then add whatever cheese you think sounds good. I prefer sharp cheddar if you want a cheesier tasting mac and cheese. Oh, and use panko bread crumbs. They are a bazillion times better.
Seat of the pants - start with white sauce, add cheese (I like to mix a creamy cheese with a sharper cheddar), add some pepper, mix with the noodles, put in glass dish, cover in broken crackers (saltines, stoned wheat thins, or what-have-you) and bake in the oven for 20+ minutes.
You never know what kind of obsessive compulsive crazy person you are until another person imitates your behaviour at a three-day. --Gry2Yng
The recipe on the back of Mueller's elbow macaroni plus some extra cheese for good measure. Choose any cheese you like. I like to use a vermont white cheddar and a extra sharp cheddar. Cumin adds a smokey flavor.
Shula's restaurant makes a fabulous crab mac and cheese!!
ETA: To make the process a little quicker on the prep end, I just cube the cheese rather than grate.
Served alongside a smithfield spiral ham? Very very good, and my preferred dinner, along with green beans or collards, depending on what looks the best, to cook for company that is warned to come hungry.
Consider me a mac and cheese purist. I happily experiment with cheeses- my current favorite mix is sharp chedder, fontina, and a little gruyere, but any other items put in there? No! I can only understand bread crumbs, which I do not personally agree with but will tolerate.
Put a lot of grated cheese in the bechamel sauce, until it turns really yellow. Put a lot of cheese on top, and maybe buttered bread crumbs or finely crumbled ritz crackers with melted butter mixed in. Or get Publix ready to go, dump it in a casserole dish, put cheese and bread crumbs on top and bake-no one will know the difference.
I sometimes add some smoked cheddar (with the sharp) for a little extra "zip" with a curly pasta. Can never can have too much cheese and the different shaped pasta gives more "surface area" for the sauce to stick!
Those are the "different" ones I have - I also have a few classic types. If you find a recipe you like that doesn't have breadcrumbs, just add some. Melt some butter (start with a couple tablespoons if you are baking in something like a 10" pie plate), mix it with a bunch of panko crumbs, then sprinkle a nice thick layer over the top. I get the Progresso brand herbed panko, but they also have a regular panko.
Also, I think there's an Ina Garten recipe called "Grown up Mac and Cheese," or something like that. I don't have it handy but remember thinking it looked good. Also try searching the mac n' cheese recipes on Martha Stewart's site to see if any pop out at you.