Second Language

For someone who only knows English, what does everyone think is the best supplimentary language to learn. I'm thinking German, since it's used through a lot of Europe (or at least gives one a better chance of communicating with someone from some parts of Europe) and is similar to English.

Oh, and d)being useless cunts (WTF has Sweden contributed to the world in the last 200 years apart from ABBA and Carl von Linné's studies?)