The terms "Struts Action Framework" and "Struts Classic" are synoymous. They both refer to Struts as it currently exists and has existed for years. Struts has a large base of applications and developers, so it isn't going away any time soon. Making the choice to use this framework for a new application is a relatively safe one.
For developers who wish to make the switch to Java Server Faces (JSF), but keep some of the features of Strus, the Struts Shale framework has just recently been unveiled. Here's a link that tells a little more about it.