The Oracle of Omaha's Latest Riddle
Article on Berkshire Hathaway chairman Warren Buffett, who has spent lifetime, living and working in Omaha, Neb, trying to integrate personal values such as honesty, trust and openness with business, political and public worlds around him; Buffett is set to meet in Manhattan with Justice Department, Securities and Exchange Commission and New York State Atty Gen Eliot Spitzer to discuss wide-ranging investigation of insurance industry practices, including finite reinsurance, some of which involve Berkshire subsidiary, General Re Corp; General Re, major reinsurer that figures prominently in investigations, sold products to American International Group in deals that investors say allowed AIG to enhance its financial statements; photos; drawing (M)