MS08-067 Unscheduled Security Update

Microsoft does not normally release a security update outside the regular patch Tuesday. That they have chosen to push out this update indicates that it should be taken seriously.
http://www.microsoft.com/technet/security/bulletin/MS08-067.mspx

“This security update resolves a privately reported vulnerability in the Server service. The vulnerability could allow remote code execution if an affected system received a specially crafted RPC request. On Microsoft Windows 2000, Windows XP, and Windows Server 2003 systems, an attacker could exploit this vulnerability without authentication to run arbitrary code. It is possible that this vulnerability could be used in the crafting of a wormable exploit. Firewall best practices and standard default firewall configurations can help protect network resources from attacks that originate outside the enterprise perimeter. The security update addresses the vulnerability by correcting the way that the Server service handles RPC requests.”

Home systems should really be set to install patches automatically.
At work, the processes to deploy patches are hopefully well defined.
So there is really no point in running around in a panic, its just not that interesting. Potential for a new blaster just doesn’t equal a new blaster. People are much more likely to have established patching programs and have personal firewalls in place. So get patching, but no need to freak out.