I was browsing InfoQ this morning and read a blog post about how Erlang may be the next big language after Java.
I tend to disagree with the points made. Erlang seems to me to be more of a niche language, much like Smalltalk. Sure it's powerful and grand, but the next big language it isn't. The syntax, from what I've seen, isn't what programmers are used to. That alone is probably the biggest strike against it. Even if the syntax was more C-like, the language isn't well known outside of the functional language geek crowd, and it lacks a "killer app".
If you want my honest opinion, I agree with language that Steve Yegge alluded to in his The Next Big Language post a while back: Javascript. It's used more than most people want to believe, it's functional, object-oriented, and embeddable. In short, it's everywhere. The only problem is that it's current implementations don't make concurrent programming any easier. But since when has the next big language ever been about the right tool for the job?
