Microsoft has published a nice IT Show Case about 64bits in Exchange server 2007 environments.
Description on how running Microsoft Exchange Server 2007 on the 64-bit platform enables Microsoft IT to keep pace with ever-increasing performance expectations, raise mailbox quotas, lower storage costs, and eliminate tape backups to save additional costs.
Check out it here: http://www.microsoft.com/downloads/details.aspx?familyid=f31e7541-f63a-4b7d-b8d2-3794c4dc3329&displaylang=en
Technorati : 64-bit, Exchange Server 2007
Del.icio.us : 64-bit, Exchange Server 2007