Six years after battling her way to a Senate seat from her newly adopted state by campaigning night and day, Hillary Rodham Clinton is coasting toward re-election _ and piling up money that could go toward a run for the White House in 2008. The New York Democrat has had no well-known GOP opponent in her bid for re-election since prosecutor Jeanine Pirro dropped out in frustration in December. The Republican expected to step in, former Yonkers Mayor John Spencer, is a no-name in most of the state, and polls show Clinton with a commanding lead against all potential challengers....