I can't think of much to add to the original 15, but I suppose if you're Canadian, you're probably thankful that Benedict Arnold got stomped in his horribly bad invasion of Quebec at the start of the revolution.
Can you say "Northern United States"?
I wouldn't at all say stomped. In fact he was not defeated, merely not able to further advance due to the logistics.
Battle of Yorktown would be more decisive.
I would agree post 1851 of adding Midway and Stalingrad. Both turned what looked to be certain defeat into victory and turned the tides in those theatres.