The "best" cut of beef is so esoteric it is ridiculous. It all depends on what you are going to do with it. If you're just going to stick it under the broiler or over the coals and sear it, you want to pay the big bucks for a filet mignon, a porterhouse, a T-bone, etc. This is what you do if you want rare. If you are going to long-cook it, then you go for the tougher cuts with more sinew. And you don't take off ALL the fat, leave some on. To me, lean meat sometimes means tough meat. My latest "favorite" is something called a Flat Iron Steak (I think related to chuck?). I beat the living daylights out of it, then either marinade or dry rub it. Sometimes I slice it thin before sort of stir frying. The cut you buy depends on what you are going to do with it. I'd never put an expensive cut, for example, in Bouef Bourgonion, chili, etc; something I'm cooking all day. There is more flavor in more inexpensive cuts, and when you're through, they will be tender.