For a half-century, David Ogilvy has blazed across the advertising skies. The tail of his comet stretches from the pre-television era and Madison Avenue in its gray-flanneled heyday on through the creative revolution and into the world of global mega-mergers. All the while, Ogilvy's sharp, iconoclastic personality has illuminated the industry like no other adman's. Now "retired" to his chateau in France, Ogilvy still has strong, informed views about the state of advertising and the fate of agencies. Here are his latest, and perhaps last, confessions.