"Tom Coughlin sounded as if he couldn't get to Albany fast enough yesterday to begin defending his Super Bowl championship, the sights and sounds from the Canyon of Heroes, from the ring ceremony at Tiffany's, from visits to Walter Reed Hospital and the White House suddenly in his rear view mirror. Full speed ahead, to a new season, and a new challenge, and the same old naysayers who will argue that the Super Bowl XLII Giants were a fluke. What would the only Giants head coach not named Bill Parcells to win a Super Bowl championship say to them? "What I would say is, 'That's a lot of garbage,' " Coughlin said swiftly in a telephone interview with The Post. "