Which language should I learn and why? Please read the details!?

I'm getting a language software for my 15th birthday in whatever language I want(: I already own Spanish software, so don't say that. I also hated French in school, so probably not that either. I'm most interested in Japanese and German; Japanese because of my love of the culture and anime/manga, and German because of my heritage and my love of their history (pre WWII). which one would be best? If both of those are useless, then what other language, other that French/Spanish, do you recommend?