America's current fascination with vampires was demonstrated again on Thursday when The Vampire Diaries delivered the largest audience ever for the CW. The premiere of the series attracted 4.8 million viewers, particularly impressive given the fact that it aired opposite Big Brother , which is drawing the biggest audiences in the history of the reality series (Thursday's recorded 7.6 million viewers) and NBC's telecast of the NFL pregame show and kickoff, which drew 12,25 million viewers in the 8 00 hour. Diaries also attracted the most teenage girls of any show airing on Thursday. The big winner, of course, was the Tennessee-Pittsburgh NFL telecast, which averaged 18.85 million viewers, peaking in the 9 30 p.m. half hour with 20.13 million.