This topic has come up in different forms before. There are some serious and not-so-serious comments about Mandarin here:
Russian has never been debated before, but I have a feeling that it is "yesterday's language choice", perhaps in the way that German is increasingly being sidelined in some schools in favour of Spanish. It was popular at one time because of the Cold War, oddly enough, and was a reasonably well subscribed course at my Uni, but they seem to have dropped it completely.
The only person I ever knew who used Russian in his future career went to work for GCHQ. Of course, he couldn't actually tell me that he used Russian in his work, but I sort of made the connection for myself!
Personally I am a huge fan of Latin as the root of so many other languages.