I'll have a think.
As a starter Address book and Contacts are two different things. Contacts is like a PC version of a paper address book with all people on it that you create so it will include those without an email address.
Address book is a database with all those in contacts who have an email address.
In Vista Outlook Express is replaced by Windows Mail which has new features. In addition there is Windows Calendar which is a useful strip down of Office Calendar and Windows Contacts wich again is a stripped down Office Contacts.