Mozilla and Google - Exchange Killers at last?

phase_9 writes: "The latest version of Mozilla Thunderbird may still only be in beta but already the user community have started creating an extensive set of viable Exhchange killers. One such example is the latest mashup between Thunderbird and Google Calendars, providing bi-directional syncing of calendar information from both the client and internet. How long will it be before open-source software can provide a complete, accessible office suite for a fraction of the cost that Microsoft current impose?"