I divide my "steak" into to categories:
1. Simple: steak, grill, (maybe spices) & go.
2. Complex: steak that has been fiddled with (marinades, aged, etc.)
Simple
#1 Ribeye. Tender & flavorful, what's not to like.
#2 Sirloin. I skip the t-bones & porterhouses, as they are a bit too fatty & bony for my tastes. If I am not paying the money for ribeye, get me a nice, lean sirloin and call it good.
A filet/tenderloin is fine, just lacking in flavor. There is a reason they wrap them in bacon...
Complex
#1 London Broil marinaded a bit in cranberry juice concentrate, sliced thin, and served med to med-rare. This is essentially a lean cut of round steak. I like to get it as fresh as possible so as to maximize the time I feel I can marinade it in the cranberry juice. I like to go two or three days minimum if I am to cook it soon. I will freeze it, marinade & all if I get a good deal and don't expect to eat it for a while. Something in the marinade/freezing process seems to break up the muscle fibers and tenderize it. Yum, yum.