For me, first impressions depend on location. If I am in someone's home, or my own then my first impression of a good meal is by smell. But if I was in a restaurant where it is hard to always get a good smell of your individual dish, then it would be sight. But there is a however to that as well because Indian restaurants (or any country that uses a lot of spices and herbs) can also smell wonderful as you walk passed or into them, and then it would also be smell. So I have answered smell because my OH often says as he walks through the door that his evening meal (and mine for that matter!) smells really good etc.