The new version now has Exchange 2003 SP2 integrated into it, allowing for storing 75GB of data of e-mail and other items on the user private database store.
It also has a version WSUS allowing you distribute patches to workstation, but also provides some basic network management capabilities. SBS 2003 R2 WSUS also integrates its reports with the general SBS reporting.
For more information:
http://www.microsoft.com/windowsserver2003/sbs/default.mspx