This is an article from Nicholas Kristof about what languages your kids should be studying. He says that it's good for kids to learn Chinese, but the real go-to language that people in the US should be learning is Spanish. Spanish is all over the US, but more importantly it's the language of most of our country's neighbors, which all happen to be in times of rapid economic expansion and increased political relevance. Beyond this, Spanish is not hard to learn for an English-speaker, at least not compared to Chinese.
This article struck a chord with me for a number of reasons. First off, I speak Spanish, love it as a language, and agree with Kristof that it is ever more relevant in today's world, especially today's US. Secondly, I am studying Chinese myself, slowly but surely. I know about 60 words and their symbols--only about 2940 to go before I'm fluent! And honestly, apart from having to learn lots of symbols, I find Chinese to be an easy language to learn for an English speaker. The grammar, tenses, adjectives, etc. are oddly similar to English--no tricky conjugations to master, for example.
Sadly, Kristof points out that many people are ignoring Spanish in the US. My experience confirms this. Growing up, my public grammar school's gifted program taught us [decadent] French as our foreign language, while the "regular" kids learned [vibrant and relevant] Spanish. These days the gifted program is teaching Chinese! It seems that Spanish is too proletarian, too common, too immigrant-y for high-achieving people to pay attention to. It's their loss though--while the children of the elite are stumbling along in bad Chinese, their Spanish-speaking counterparts will be making new deals and new friends in the US and the hemisphere!
So I urge my readers to go out and learn Spanish. It's not hard to do so in the US--there are schools, neighborhoods, newspapers, libraries, TV shows, and any other number of resources to learn the language. My mother is almost 70, and she's becoming conversational in Spanish after just a year and a half or so of semi-intensive study!