Why eight? Eight seems like a pretty odd number, but lol I guess that's just me. Knowing nine total languages is a pretty neat talent, and can certainly land you great opportunities. I would start with Latin. Yes, Latin, the dead language. In addition to the pure historical aspect of Latin, many languages have Latin roots, and I believe it would be easier to learn some languages when you have a background in Latin. I would also like to learn Spanish and Mandarin Chinese. English, Spanish, and Mandarin Chinese are the top three most spoken languages in the world, last I heard. Naturally, this would not only be very convenient for anyone who'd like to visit a Spanish- or Chinese-speaking area, but it is also great for business and finances as the United States has many relations with Chinese industries. Building on that, I would imagine Japanese would also be a great language to learn. The U.S. trades with Japan for much of its technology, so Japanese would also be great on a business level. Besides that fact, I've developed quite an appreciation for the Japanese and their culture since I played Okami. Still maintaining practicality, I would also learn French, considering that Canada, a huge partner of the U.S., is mainly English- and French-speaking.
With my remaining three choices, I would pick languages that would simply be fun to know. Greek stands out as one such language. I love Greek mythology, and Greek characters just seem plain ol' cool to me. I would also like to learn Arabic because Middle Eastern culture interests me, and when watching shows with scenes set in Arab countries (such as N.C.I.S.), it would be cool to be able to understand the characters without having to read the subtitles they provide. Finally, with my last pick, I would choose Russian. Russian culture isn't one of my favorites (though it does still interest me). My reason for picking Russian is probably a pretty petty one: One of the bands I used to listen to has an entire rap written in Russian, and it would be neat to be able to understand it. :bleh:
So...
1. Latin
2. Spanish
3. Mandarin Chinese
4. Japanese
5. French
6. Greek
7. Arabic
8. Russian