Yeah, I thought that online email was a great option, and for blocking viruses, it may be.  I happen to prefer local machine based email.

I have messages and attachments stored ON MY COMPUTER, where I can view them regardless of web availibility and download speeds.  When I am out in the field, I may need a particular piece of email now.

I am not subject to the limitations of space or time allowed by an online mail server.

It's easy to manage my address book.

If I change ISP's, my email goes with me.

To many people, these things may be no big deal, but when you spend years putting together a data storage and transfer system based on local storage of email, you prefer to keep things that way.