As most people on here, I've mostly only tried the Western versions of the food. I've tried genuine food from England, Italy, and America, and I'd rank them like this:
1) Italy (even though I'm not a fan of pasta, theirs was spectacular, but their pizza wasn't that amazing)
2) England
3) America
If I had to rank them all based on even the Westernized versions, I'd say this:
1) Italy
2) China
3) England
4) USA
5) Indian (butter chicken and chicken korma curry are the only two things I like)
6) Mexican (I only like one Mexican restaurant, which is in Detroit, so I can't really judge)
Germany has EXCELLENT food though. Some of their little pubs and even their beer halls have really good stuff, so that'd be up there as well. I'm use to Canadian food, so I don't find it anything spectacular.
If only I ate at more places other than McDonalds on my travels, I'd be able to give a better description of what countries are good and which are bad. I tried one traditional Slovakian dish which was just okay, kind of got gross and too cheesy after a while (if that's possible).. The Hungarian mushrooms and cheese were really good though.