Well first off, there is no one good way to cook a steak, since the term "steak" can mean anything from a bit of the tenderloin to a London Broil.
Steaks should be handled differently depending on the cut of meat. Steaks with lots of fat marbling (and therefore, flavor), such as a New York, or T-bone, have a naturally assertive beefy flavor, and can be eaten plain or very lightly seasoned. Fillet mignon OTOH, with it's lack of fat to provide flavor, is just begging for a sauce or crust of some kind to bring some much-needed flavor to an otherwise bland cut of meat. Also, depending on the cooking method, flavor additives become more useful. Grilling a steak brings lots of wonderful smoky flavors to the palate. But adding wood chips will generally overpower the flavor of a steak. A sauteed (or pan-roasted) steak will be better if you make a sauce with the fond that is left in the bottom of the pan. The fond is part of the flavor of the meat, just stuck to the bottom of the pan. It simply needs a few aromatics, some wine, and a little chicken stock to release that flavor.
Personally one of my favorites of all time is a pepper-encrusted fillet mignon served with a port-cherry reduction, some oven roasted green beans, and a glass of Syrah. I cook it rare, starting on the stovetop and popping it into the oven once the crust is nicely developed to allow the meat to hit about 120 degrees.
I like my flank steaks a little closer to medium, say about 128 - 130 degrees. Unless I grind my own meat, hamburgers get cooked to 160 degrees.
And yes, chefs do get a little annoyed with people who order their fillet mignon well-done. It's a little like asking a computer geek to bring you a tricked-out MacPro with maxed out RAM and two 30" monitors so that you can send some email and surf the web in your spare time. Sure you'll do it 'cause they're paying, but it hurts you inside knowing that the machine will be essentially wasted on that person.
