Surrounding themselves with the right people is among both the best things about being a leader and the most difficult, say 260 presidents and CEOs of U.S. companies surveyed by Caliper Inc., an international human-resources consulting firm based in Princeton, N.J. "When you are leading an organization, surrounding yourself with the right people becomes an either-or situation," interprets Herbert M. Greenberg, Caliper's president and CEO. "Either you hire and develop people who you thoroughly enjoy working with, people who are bright, engaging, conscientious, and adept at solving problems -- or the chemistry just isn't there, and leading becomes a constant battle and, at best, an enormously unpleasant chore."