TechRepublic, an IT resource of the publisher ZDNet, has a good summary of the security features of Windows 7 which are especially pertinent to system administrators.

While some features like BitLocker, a drive and volume encryption mechanism, and DirectAccess, a VPN-like remote access implementation, are available in the Enterprise edition only, Windows 7 generally adds more security measures than Vista in a less obtrusive manner. Although operating system security is no substitute for vigilance and user training, it's an important componet and defense against present and emerging threats.

Kevin Lo | Senior Program Manager, NetSquared.org | a part of TechSoup Global