Jbehave or Just Selenium Webdriver and Junit

I think you need to separate some concepts. JBehave is a framework that provides ways to run Acceptance Tests using stories that was written using Behavior Driven patterns. You can use it to execute acceptance tests against any kind of system, including Web with Selenium HQ. With BDD the focus is on what your customer told you about what the system must do. So the main goal is clear communication !

So, off course you could use Junit + Selenium... but your tests will be more technical.