Auto-Auto Reply

I've worked with five email programs in the last five years: Entourage, Outlook, Thuderbird, Gmail and Mail for Mac.  None of the five have an automatic "out of office" auto reply.  For some reason each program requires you make a special rule for your incoming mail and then type out a reply and then turn the rule on.  With as much travel that is done now it seems like there should just be a button you hit that turns it off or on.  Then if you wanted you could go into your settings and make special rules or change the text or whatever.