Windows Server 2008: Object Accidental Deletion Protection
Source: Global Knowledge
Disaster prevention is better than disaster recovery, although both have value. Microsoft has built some new disaster prevention capabilities into Server 2008, one of the more useful of which is accidental object deletion protection. Take a look at enabling this feature - and not just for new Organizational Units, but for old ones, and for critical user, computer, group, and even Group Policy objects. It's a useful new way of applying the old Access Control List concept, and reducing the likelihood that one dumb move will ruin your whole day.