I would highly recommend Devise - it works perfectly with Rails 3, and in my experience the developers are very helpful in answering questions in the Devise Google Group. There are also two railscasts on Devise - http://railscasts.com/episodes/209-introducing-devise and http://railscasts.com/episodes/210-customizing-devise. CanCan is an authorization solution that can be used in tandem with Devise - check out the Railscast, this plugin again works great with Rails 3. Hope that helps!