The Searing Advise is spot on. So many people cook burgers like you had mentioned on direct heat at an even temp till they are done, but why wouldn't you cook a burger like a Steak? Sear it up, then let the inside get to temp.
As far as my burgers, I do grind my own chuck, and often mix in a bit of ground pork, but if you cant I would recommend grabbing some fresh ground chuck from your local grocer/butcher, and mix it up yourself. I have only ever done burgers without anything but S&P like one time, and it was because I had ground ribeye and didn't want to do my usual, but otherwise I do the following and they are always tasty!
I always add fresh minced garlic (a bunch), Salt, Pepper, Chicken bullion powder (I know not beef?.. I think it adds a better flavor), Chili Powder and an egg or two depending on how much meat you have. Mix it up good and press into patties. For me just the taste of ground chuck alone isn't amazing, so I like to season them, sometimes ill even do an excess amount of garlic for garlicburgers.
I personally like my patties bun sized in diameter and thin like the thickness of the standard frozen boxed patty. I think this lends to the perfect Meat-to-Bread-to-Seasonings-to-toppings ratio, but I know people like real thick burgers too, so when I have a party ill throw some of those on too.