The scary part:
Outlook 2000 SP1 and Outlook XP prevent the virus issue from happening. Outlook 97, 98, and 2000 unpatched do not. Neither does Outlook Express.
That being said:
Outlook is the only way to practically connect to an Exchange server and do collaboration. There are only Exchange and Domino/Notes in that space that have much commercial support. That's the only way that it works.
I've gotten most of the Outlook features working in Evolution and OS X's mail program, because it uses modified IMAP headers

. However, meeting requests use those headers and send those as email messages. I guess that's what the $70 add-on does.
Now get me an non-MS exchange-compatible program, and I'll be happy.
Mitch