I'm going to take a slightly different approach in my comment here. Yes these are great utilities. What I would like to know is how many people acting as DBAs ( whether formally or not ) actually have local administrator or even domain administrator type rights.
In my case, and I suspect in many small to mid-size companies adopting sql server, the DBA role hasn't been formalized and many of us can only execute commands such as these if logged into a query window as sysadmin -- in other words you are doing xp_cmdshell work as if you were the sql service.
In my case I'm beginning to wonder if it's worth even pursuing this role until it is recognized that DBA work typically requires some form of administrator rights. You wind up with a situation where the systems group has the rights, but no knowledge of or desire to administer sql server, and others with knowledge and desire, but no rights other than sql sysadmin.
Picture fixing an out of sync log shipping plan by doing DOS commands via xp_cmdshell.