With the exception of Canada & Mexico, which I was only there once, I have never been out of the US.
Out of the US my choices would be Italy/Sicily, England, and maybe Greece, which I hear is nice.
In the U.S. I have been to Florida twice, and several Midwest states (Wisconsin, Ohio, Indiana), though there are no major things to see IMHO.
I would love to see more of the East like Massachusetts, Vermont, just because they look neat.
TIS