Being bi-lingual is amazing. I for one am tri-lingual. English, Polish, Swedish. Good luck teaching yourself Mandarin Chinese, I believe its one of the top 3 most difficult languages in the world. Italian and French are wonderful languages to know if you want to pick up chicks since they're both very romantic sounding, nothing says 'i want my richard so far up your ass you'll stuff out your throat' like 'Tu est mon ami'
If you're looking to stay in America, its highly reccomended to learn Spanish. For me, I decided to drop out of Spanish after 3 years because its going to be completely useless to me in like 2 years since I plan to study and stay abroad.
If you ever need help with languages, feel free to PM me, I absolutely adore languages, they just baffle me how the world is so diverse in so many aspects.