My #1 con choice is A-kon, located in Dallas. It's the oldest anime convention on the North American continent and was named after one of my favorite classic anime titles, Project A-ko.
I would also like to attend Anime Expo, Otakon, Tokyo in Tulsa, Everfree Northwest, and a Star Trek con.
As for international, Anime Evolution is the first one that comes to mind. I attended back in 2010, and while there were some pleasant moments, the overall experience was a slap in the face. From what I understand, they "closed the door" for a year or two and came back. I'd like to see how much they've improved.
I know that there are a few others in Canada that struck my interest, but their names elude me at the moment.
There's also a con in Japan that I discovered while doing a research paper a few years ago. It sounded amazing, but I have also forgotten its name. I can just look at the research paper again, though.