Technet offers some excellent security recommendations for protecting Windows 7 and Server 2008 environments
Windows 7 – Recommended Corporate Security Settings
QUOTE: This guide is a reference to the security settings in Windows Server 2008 R2 and Windows 7 that provide countermeasures for specific threats against the current versions of the operating systems.Many of the countermeasures that are described in this guide are not intended for specific computer roles in the companion guides, or in some cases, for any roles at all. These countermeasures help ensure compatibility, usability, manageability, availability, or performance. Generally, as security increases, functionality decreases, and vice versa. However, there are exceptions, and some security countermeasures actually help improve functionality.