Servlet 3.0 has not yet been released, but it looks like it's very close. The most important changes in 3.0 are: Pluggability, Ease of development, Async Servlet, Security. Whether or not these are important to you is impossible for me to say.
The most significant of these is probably the support for asynchronous Servlets. Here's an article that describes this in detail. The full specification can be downloaded here.