DON'T LET THESE MOSTLY SMILING FACES fool you. We just as easily could have called the opening installment of the 2008 Roundtable "Before the Deluge"-that is, before the great unwinding of a quarter-century of excesses that our panelists, to a one, predict will set the investment tone for much of this year. Their forecasts for the U.S. economy are particularly sobering: a recession, or growth so tepid it will feel like one. Fortunately, their expectations for the U.S. stock market are considerably more upbeat, especially for the second half of the year.