Good question ... I've tried US, Japanese, British and Argentinian beef. My favorite is Kobe, (not Wagyu style) but the price makes it a very rare treat. My favourite is Canadian Beef. Specifically Limousin cattle (Limousin is a breed, like Black Angus or Hereford). It's what I grew up on. There are subtle flavours that I prefer with the way the connective tissue and fat melts into the meat.

Thanks to this post, I will have steak for dinner tonight.  :-)