Mexico and Japan have my number
When I was staying in Mexico for a few months, my then-girlfriend quite enjoyed her arrachera, or skirt steak. She grilled it in butter, then add rosemary from her garden, and some Maldon salt. Those meals -- along with guacamole and salsa molcajeteada (salsa made with a mortar and pestle) -- were always excellent.
Crossing the Pacific, I've tried Kobe, Matsusaka, and Omi beef. Matsusaka stood out, for the marbling and the sweetness. But shoot, they were all top-notch, particularly when served with garlicky mashed potatoes.
My favorite way of eating steak, besides with guacamole, is au poivre.