Last month the 69-year-old Wall Street options veteran put off what might have been retirement No. 4 to become chairman of the International Securities Exchange, the all-electronic options market. A vice chairman of the ISE from its launch in 1999, Riley has known ISE president and CEO David Krell since their days at the NYSE's old options business. "I think we still have a lot of work to do," says Riley. "I'm excited."