Dick Enberg returns for his second season as the lead announcer for Westwood One's Thursday Night Football coverage.   With one of the most recognizable voices in sports broadcasting, Enberg can also be heard as the a play-by-play announcer for THE NFL ON CBS, college basketball, The U.S. Open Tennis Championships and as a contributor on the Masters.   Previously, Enberg spent 25 years with NBC Sports, beginning in 1975 as a play-by-play announcer for college basketball, and has taken on assignments from the Super Bowl to the NBA All-Star Game and everywhere in between.   Prior to joining NBC, Enberg was the radio voice of the Los Angeles Rams and UCLA Bruins.   Enberg's work has garnered 14 Emmys, 9 Sportscaster of the Year awards, the Victor Award for top sportscaster of the past 25 years and a star on the Hollywood Walk of Fame.