Caribou and moose are among my favorites, but among commercially raised meats I'd have to say bison/buffalo. I barbecued some steaks side by side with beef for some friends of mine and they couldn't believe how much better the bison was. Lamb is also awesome - a butterflied leg on the barbie is the way I like to do it. Some people don't like the smell but they just don't know how to cook it.