If you really want desktop users to dump Windows you need applications. Today, we got applications.
Eudora is going open source, and its basic technology will now be based on Mozilla's Thunderbird. Many heavy e-mail users have always preferred the Qualcomm client to Microsoft's Outlook Express, and putting the technology together with Firefox in Mozilla is just going to make the bundle that much better.
Google is combining its online writing and spreadsheet tools, enabling easy collaboration on the Web for users of both. That gives Google an entry into what had been Microsoft Web Services. Learn more here.
More important the word processor, originally called Writely, supports the Open Document Format of Open Office. That means you have both a client and a collaborative tool under ODF.
Is desktop Linux ready for the mass market now? What else do we need?