Over the last several months, I have been interested in passively watching the Tiobe Programming Community Index. While Java holds onto its #1 position consistently and other languages such as C# (steady rise), C, C++ (starting decline), Perl, Visual Basic, and PHP have consistently been ranked high, it has been interesting to watch the small bursts of enthusiasm for a wide variety of different languages. In particular, it has been interesting to watch the rise in popularity of Ruby (27th to 9th in ~3 years) and ActionScript (last rank was #23). I really like Java, Ruby, and ActionScript and apparently so do a lot of other people (at least there are a lot of searches online for terms related to these languages).
I was particularly interested in the Paul Jansen article Programming Languages: Everyone Has a Favorite One that appeared in the May 2008 edition of Dr. Dobb's Journal. He summarized some of the same trends I was seeing in this index of programming language popularity based on search engine searches. In particular, I have witnessed similar trends among colleagues related to programming languages he specifically mentions in the article such as C#, Java, Perl, and ActionScript. I also agree largely with his assessment about the Next Big Language (NBL).
The Tiobe web site with this index is at www.tiobe.com.