I never use a recipe, either. I make it the way my mother made it - and hers was always so good! I think as a kid I didn't fully appreciate it, but we were fortunate enough to have her make it for us as adults, and it was a real treat!
Much the same ingredients that most others use, and a similar process for meatballs. Super easy.
I often use ground turkey instead of ground beef or pork. And I stick with the basics. (Turkey might be a little drier, but not much when you add the eggs, milk, and even chopped onion which adds moisture.)
Ground meat, a chopped onion, Italian bread crumbs, eggs, milk, salt and pepper. (Meatballs get lots of garlic.)
I don't put sauce or anything on the top - but always serve with cold ketchup, and likely mashed potatoes. Comfort food at it's best. (To some, plain ketchup might be boring, but I love each bite with a nice swipe of it as that is how I'm used to it. So good.) Call me a purist, I guess.
I saved the recipe above with the bacon and the tangy sauce as maybe I'll make it for a special occasion (I have the feeling my son would love it), but I think the bacon and the cup of Parmesan, although undoubtedly delicious, adds a lot of fat. I love, love, love Parmesan, but not in my meatloaf. (Or in my meatballs, really, although I love it fresh and shaved on top of my meal with sauce.) Meatloaf doesn't have to be a big production.
Top with ketchup. 
Yes, yes, YES!! No matter what other ingredients you choose, make sure you use WET BREAD instead of bread crumbs. You won't believe what a difference it makes for a tender, less dense result. (I use water instead of milk and squeeze the excess out before mixing the wet bread into the meat).
