The Olympics without a doubt. Has the best players from the best teams and is good open, clean hockey. The players seem to want that the most as well, so it gets the best effort.
That said, I would like the World Cup to be elevated to the primary Hockey tourney, like the Football World Cup. As can be seen in Men's basketball, the Olympics is not necessarily the best place for multi-millionaires to be partipating. But still, right now, the Olympics is the tourney where all the top nations give it their all.
Previously, the Olympics were of course a bit different.
I never watch NHL hockey so I'm glad It's not in the poll. I prefer the international game. I'd pick the World Championships as my second choice.