I live in the US and have been to almost all of the states thanks to cross-country road trips with my parents, and parts of Mexico and Canada as well. I think the only states I haven't visited were Alaska, Arkansas, West Virginia, and Kentucky. I've lived in both California and Nevada, and have visited New York, New Jersey, Massachusetts, and Florida many times due to family living there.
As for other countries... When I was very young, my parents and I lived in Singapore for a while because of my dad's job. We traveled to nearby places like Taiwan, Hong Kong, India, Malaysia, and Indonesia while there. Later on I've visited other countries such as:
France - I was in Paris for a few days, but nowhere else in the country. I truly regret not drinking any coffee or wine (though I was too young for the latter) while there.
England - Mostly in London, except for one day trip where I went up to Oxford. This was in the same vacation as Paris and was only a week long, so there wasn't much time to see too much.
Japan - This was a week-long trip with my dad; we were in Tokyo, Kyoto, and a day trip to Mt. Fuji. We were there right in the middle of cherry blossom season too.
Italy - My family and I spent just over two weeks there last summer and went all around mostly the northern half of the country.
My dad and stepmother and I are tentatively planning to visit South America next, though we're not sure when. I'm also planning to take my mom to Ireland and the UK once I have the money to do so.