I think the highly-talented Maple Leafs have a shot to win the Stanley Cup this season. Toronto wasn't that sharp in its opener against Montreal, but came back from a two-goal deficit to nip the Canadiens in overtime. 
I expect the Maple Leafs to play better against the Senators. Toronto has the edge of already having played a game - not to mention a huge advantage in talent - while Ottawa is making its season debut. 
The Senators were the second-worst team in the league last season. The Senators are breaking in many new faces and without preseason they likely will start slow.