The Perfect Hamburger
Yes, the perfect hamburger is attainable, and simplicity is the key. Of course nothing is perfect for everybody, but I've found this to be the closest way to perfection to cook a hamburger.
Meat
The meat should be somewhere between the regular fat-laden hamburger you can buy in bulk and the super-lean meat you can buy for twice as much. Too fat and your patty distorts and shrinks to nothing. Too lean, and it won't be cohesive enough to cook well, and will stick to the grill mercilessly. Ive found the 80%-90% range to work well. Make a patty about 3/4-inch / 2 centimeters thick and mold it into a circle slightly larger than the bun you will put it on. If you prepare your own meat you can cook it rare. If not, try to get just-ground meat so you can aim for a faint pink stripe as described below.
Seasoning
Nothing arcane - no rare herb, weirdly-named spices - just a light sprinkling of garlic powder and salt. Garlic has the magical quality of bringing out the best in beef. Too light and the effect is dulled, too heavy and you taste garlic and not the beef. One light pass is enough. The salt and garlic should go on just as you are about to put the patties on the grill.
Grilling
A gas grill with lava rock is ideal - preferably one that has been in use many times so the ghosts of grilled food past contribute to the overall taste of the patties. Since each grill is different it's hard to actually quantify the temperature and timing here, but I will try. Start with the grill really hot. You may want to brush the grate with vegetable oil prior to heating to help with sticking.
Put the patties quickly on the hot grill. Wait just about a minute and flip them over - we're looking to sear both sides as quickly as possible. As soon as you flip them, turn the grill down to whatever your medium is. Wait another minute, then flip the burgers again, turning the patty 90 degrees to cross-hatch the grill lines. Wait about two minutes, flip again, wait two minutes more, then remove the patty. This should result in a nicely browned patty without charring, and the internal appearance should be juicy and brown, with about 1/3 of the width lightly to faintly pink. You may have to experiment a few times to adjust this to your particular grill temperature and meat - but it shouldn't be hard.
Assuring perfection
Here's where things get subjective. The perfect hamburger is the one with everything you like on it and nothing you don't. Great combinations for me may include sauteed mushrooms, muenster cheese, or even a fried egg with condiments on a lightly toasted homemade bun. Whatever your favorite additions are, add them here - then enjoy!