American Benefits Council today suggested President Bush appoint Alan Greenspan as the head of a national task force to study Social Security, Medicare and Medicaid. Mr. Greenspan, who on Tuesday retired as chairman of the Federal Reserve Board, is "intimately familiar with nation's economy and chaired the historic 1983 commission that saved Social Security from the brink of bankruptcy. He has the talents and the stature to make this critical effort succeed," James Klein, president of the Washington-based association, said in a news release. "He's tan, rested and ready and as of today, he's got extra time on his hands. He's the logical choice."