Nothing requires you to use a Hotmail address when creating a Passport account. So you can set the e-mail your choice for a more unified management of all services (MSN, webmail, etc.)..

We begin by creating a new Passport account. To do this, go to the following address: Windows Live ID.

You just have to fill out the form and confirm your registration.

This formality accomplished, launch Windows Live Messenger and log in using your e-mail address.

Note that you can now use your Windows Live ID at all sites using Passport.

In short all the advantages of an account (POP or IMAP and non-HTTP) without the inconvenience of a Hotmail address that could not easily repatriate its messages directly on your PC.