She's danced on tables until 3 a.m. with R.E.M.'s Michael Stipe, conducted the first interview with President Clinton after the infamous Dick Morris debacle and commentated at galas from the MTV Video Awards to an inaugural ball. Having reached her loftiest goals, MTV News anchor Tabitha Soren has just one question. "I'm only 30. Now what do I do?" To help figure out just what to tackle next, Soren has taken a one-year respite from MTV to participate in Stanford's Knight Fellowship Program for journalists. As a fellow, Soren takes classes - minus the responsibilities of homework, tests and grades...