I agree Shane. When I was growing up we had breakfast, lunch and dinner. But then on Sundays we had dinner at lunchtime. So, as far as my family is concerned, dinner is the big meal of the day.
I now live in Spain and here people have a larger meal in the middle of the day and a smaller meal in the evening. In my house we call the midday meal 'dinner' and the evening meal 'supper', because dinner is bigger than supper.
It will be interesting to hear what others think.