Well it all depends. Ask your client what he is looking for and give him what he wants. He might be satisfied with a simple password protected directory. He might not want what i suggested above, and now that I think of it, he probably doesn't.
Let's say your client is at a gallery, and is talking to someone who would like to see more of his work. He needs to refer him to his website and if he doesn't know the password to the client area right then it would be a hassle having to wait for someone to create an account for you. So maybe that is the best solution.