I had to learn Russian in school and for the life of me I can't understand why anyone would want to do this to themselves voluntarily. Russian looks weird, sounds weird, and nobody speaks it apart from movie villains (and that not even very well). But that's just my opinion. ;-)
I also had to learn French in school and it was beautiful. Hearing French and speaking French is just great. And it was tons easier to learn than Russian.
Later I taught myself English, first by watching Movies and later by reading books (novels). It helps with the pronunciation if you read it in the voice of a native speaker e.g. a well known actor. The English grammar I read up on some websites. I need English to provide support for my software products. In the first months it took ages to write an email and I had to use a dictionary for most of the words.
Having made quite a few trips to Spain in the last couple of years, Spanish would be the language I'd like to learn if I had the time. It sounds great and half the world speaks it.
And about that weird German language. Although being a native German speaker myself, I'm not sure I can recommend learning it. Nobody speaks it outside of Germany, Austria and parts of Switzerland and it's not great fun to learn something you can't use.