Video rental system

Design a system that allows DVDs to be rented to customers.

Design a video rental system. Sounds easy enough doesn't it? How do we know if the design is any good? What principles guide us in evaluating it?

It would seem that a consensus between designers would indicate a good design (or at least an informed agreement to disagree).

Here is the Video Rental System design we came up with after a short period of group discussion.

I short order this class diagram was pulled apart for numerous reasons as will be discussed below. Feel free to find better ways of doing this and contribute to the discussion.

There are some things we did get right. Using the Many to many association idiom to create a relationship between Customer and Title for the rental transaction is good.