[edanm]

I'd vote Spanish (lots of countries speak it, which makes it a good language). Or Chinese - more people speaking it than any other language, I think.

BTW, I started learning Spanish using the "Pimsleur method". It's an amazingly easy and quick way to learn a language, If you're looking for a way to learn a new language, I recommend looking it up.

[secret]

I speak English and Spanish and was using the Pimsleur CDs to learn Japanese. I can't recommend it enough. I gave up when I had no one to talk to and yet after several years, I still remember quite a bit.