Windows 7 includes many new security features, such as AppLocker, DirectAccess, BitLocker to Go, etc., but a recent Gartner analysis suggests all this might not be as great as it sounds. Their chief complaint seems to be that most of the high security features only come in the Enterprise and Ultimate editions of Windows 7, which cost more than the Professional edition, and that some work only with Windows Server 2008/2008 R2. They then go into the pros and cons of each of the new technologies. It’s worth a read if your organization is considering upgrading to Windows 7 primarily for the added security, but you should take into account that buying comparable third party solutions would cost extra, too.
http://searchsecurity.techtarget.com/news/article/0,289142,sid14_gci1515612,00.html