Help Me Choose a Language to Learn.

I live in the United States. I am fluent in English. I know nothing of any other language. I would love to know what the most useful language will be in the future. I'm going to be dual-enrolling soon at a local university, and I wanted to take a class which is unavailable to me.

Can you suggest a language? The only classes currently available to me through my high-school are Spanish and Latin.

Spanish and Japanese will both be pretty simple in grammar, Spanish because it's so similar to English and Japanese because it's, well, it's just easy.

Spanish is becoming rapidly important in the southern U.S (but then again, it's also a required course in high school), and Japanese is nice to know if you're a video game/anime freak.