I am astounded no one has mentioned bacon yet!
Good French or Italian bread sliced thin, cheddar cheese with maybe some goat cheese or even blue, and bacon.
I love both American crispy bacon and Irish bacon which is a bit chewier but I prefer the crisp for the sammiches.
Looks like I keep distinguished company, grilled-cheesedly speaking. 
My standard recipe: [ul][li]two slices whole wheat bread[/li][li]old cheddar sliced[/li][li]butter or margarine[/li][li]garlic[/ul]I use a sandwich maker so it cooks from the top and bottom at the same time. No flipping necessary. [/li]
Also, to have the cheese melt completely without over-toasting the bread, slice the cheese as thin as you can. Two thin slices of cheese melt better than one thick one.
Garlic makes any grilled cheese sandwich better. I’ll mash some garlic in a garlic press and spread in on the inside of the sandwich during the assembly stage. Alternatively, you can use garlic butter on the outside of the bread. But this can be very strong depending on how much you use, so I usually cut the garlic butter with some regular butter.
Gather together white bread, butter, and Kraft singles. Heat a non-stick skillet to medium high. Put one or more pats of butter into the pan, let melt, then place slice(s) of bread on butter puddle. Top each bread slice with two slices of Kraft singles, then another slice of bread. Put a pat of butter on top of each top slice of bread. When the bottom slice(s) of bread is browned, flip, and move the sandwich around on the skillet so that the butter melts and coats the bottom slice. Lightly press down on the sandwich with a spatula while cooking. The sandwich should be golden brown on the outside, while the inside should be completely melted. I don’t particularly care for tomato soup, I prefer a homemade chicken or beef soup. The sandwiches are good by themselves, too. I cut them diagonally into four triangles per sandwich. That’s the way my mother did it, and so that’s the way that I do it.
Bacon can be placed between the two slices of cheese, if desired. If possible, use the bacon fat to grill the sandwiches in. Bacon grease is the ONLY acceptable substitute for butter in grilled cheese sandwiches.
We keep Kraft singles on hand specifically for grilled cheese sandwiches. They melt properly.
I’ll grill ham or corned beef and Swiss on rye, but not cheddar or American cheese. That’s just wrong. And I won’t pair cheddar with corned beef, either. That’s wrong too.
Egads, people, the things you do to your grilled cheese sammiches.
First there are only two proper breads for grilled cheese: home made white, or home made sourdough.
Second, the proper cheese is only extra sharp cheddar. (Personally, I reccomend Helluvagood’s NY Extra Sharp.) There is one instance for an acceptable substitute, but this is the normal grilled cheese chez Loki.
Thin sliced tomato.
One egg, fried hard.
For an alternative there is this, but my mother hates hearing about it. (She calls it my “fat and fat sandwich.”)
Instead of normal cheese, use mozzarella.
Instead of the egg - thin sliced ripe avocado.
bliss.
Just to explain further to anyrose, a few winters ago, the board’s server crashed, which not only incapacitated the board for a month or so (IIRC), but also permanently wiped out the previous three months’ worth of posts. Hence the name.
I think I need to go out and get some dark beer, then come back and grill me one of these. This one sounds like the best so far!
Sliced sweet french bread. (sweet is better than sourdough)
Gruyere cheese, grated or sliced thin.
Salted butter, one pat for each side.
Optional: Prosciutto, grilled then diced.
Optional: butter the bread and sprinkle with spices like oregano, basil, or garlic powder.
Fry in a non-stick pan, or put it in your Villaware Panini Press. (the bread must be buttered if it’s going in the press)
I used to prefer Kraft Plastic Cheese, but these days I can’t stand it.
Now I’m hungry.
White bread, pumpernickle bread, sourdough, rye, doesn’t matter. Velveeta, craft slices, cheddar cheese, doesn’t matter. What makes for the best sandwich is all in how you toast it.
Butter (real butter only) the top of the sandwich and place on a cookie sheet on the top shelf of oven and broil. Toasted to perfection and you must watch this continuously as it will burn quickly. Take out, flip and butter other side and repeat. Of course cut diagonally and dip in catsup as you eat it along with tomatoe soup made with milk.
I never knew there was any other way to make this until I was an adult. I have had many debates with others over the method and have converted every one I have talked to into doing it this way. Yummmmm…less greasy, crispier sandwich.
I have no bread at home, and nowhere to get some on the way back from work 
But my favourite sammich is probably regarded as an abomination by most people…
Shredded/Grated tasy cheese or “pizza” cheese (premixed parmesan, tasty and mozzarella). Mix with a couple of spoonfuls of mayo and a tiny dab of mustard. Butter two slices of bread, put a clump of cheese/mayo/mustard mix on the unbuttered side of one slice, some tomato if you’re feeling adventurous and then slap on the other slice of bread. Cook in a frypan or a toasty maker until very, very crunchy on the outside. Yum.
I usually use some type of wheat bread. Butter one side of each slice, then you take grated Parmesan (the kind in the green plastic can, also known as ‘shakey cheese’) and cover the buttered sides, kinda smushing the shakey cheese into the butter. Then put both slices cheese/butter side down into a skillet (the heat should be medium or medium-lowish.) Put thin slices of cheese (I like two use at least two different kinds, maybe cheddar and mozarella or provolone) on each slice of bread, and watch for the cheese to start melting. Then flip one side onto the other and if your shakey cheese isn’t quite brown, flip it over a few times until it is.
It’s crispy on the outside and melty on the inside and sooooo good. You can also shake garlic salt on the butter before you smush the Parm into it.
Look guys, adding things to your sandwich that aren’t cheese or butter might be good and all, but then you don’t really have a grilled cheese sandwich anymore. You have a grilled _____ and cheese sandwich.
Here is an Indian style grilled cheese sandwich. Some call it “Anglo Cheese Toast”:
Use sliced white bread. Whole grain is very good.
Mince the cheese (sharp cheddar usually). Mince a bit of onion and a bit of fresh chili (or fresh chili paste you can buy in jars). Make a paste of this cheese-onion-chili-mix with some tomato catsup (yes, catsup) and a small dollup of prepared mustard. Spread the paste between bread slices.
Then toast in the usual way in a heavy pan with a little butter or oil. OR simply spray pan (with that spray stuff) and put the sandwiches in when pan is hot, lightly spray sandwiches on top, and then turn to toast the other side as per usual.
Not too greasy. Spicy, melted cheese, and crisp toasted bread. Good stuff.
Remind me never to let you make me a ham sandwich.
Yeah, well that’s different.
It just is, dammit.
For a grilled sandwich the perfect grilled cheese sandwich sounds very fried.
Yeah, but people think you have a speech impediment if you offer them a griddled cheese sandwich.
One childhood variation of the grilled cheese sandwich that I miss sometimes is a Hot Ham and Cheese. My Dad would take regular hamburger buns, stack them with chipped, boiled ham from the deli and a slice of velveeta (mexican and/or regular) and wrap them individually in alluminum foil. He would bake them for about 10 minutes in a 350F oven and serve them up with chips or sometimes soup. The texture and taste of the chipped ham, melty cheese, and warm, slightly crisped, cheap buns with a little plain mustard is just something that I can’t really explain. It reminds me of a lot of good things.
I guess I’m stretching the definition of grilled cheese a bit with this one, but it’s homey like a grilled cheese, at least.
My childhood variation (when I was in my hate-cheese phase) had my mother making me grilled peanut butter sandwiches - great with crunchy peanut butter. Just bread, peanut butter and butter on the outside. mmmm, good.
Garlic sourdough bread, real butter thinly spread on the outsides, cream cheese lightly spread on the insides, cast iron griddle heated hot but then turned down to medium-low so the bread toasts slooooowly and the cheese melts properly. Thin slices of very sharp cheddar, shredded asiago, slight sprinkle of garlic salt and smattering of fried garlic and/or shallot, grilled perfectly golden brown then cut into finger sandwiches and piled on a plate to share with a loved one.
Runner up is dill rye with swiss cheese, and maybe a teensy bit of sauerkraut. This is for the day when the corned beef runs out first… 