Talk about a hot investment. Alexis Glick, who three years ago was managing more than 200 floor traders at the New York Stock Exchange, is being mentioned as a possible successor to Today coanchor Katie Couric. Since crossing over from CNBC to NBC's Today as a correspondent a year ago, Glick is getting increasing face time. She's seen almost daily in the 9-to-10 a.m. segment. Couric, 48, has been Today's coanchor since April '91. Her estimated $12 million-a-year contract is up in May. Glick, 32 and, like Couric, a mother of two, is a far less costly TV newbie. Do...