Don LaFontaine, whose voice was heard on thousands of TV commercials and a significant percentage of all movie trailers -- an estimated 5,000 -- died Monday in Los Angeles at age 68. The cause of death was not disclosed. At one time or another he was also the voice of all the major broadcast networks as well as TNT, TBS and the Cartoon Network. His website observed that by "conservative estimates, he has voiced hundreds of thousands of television and radio spots." Entertainment Tonight said on its own website that "based on contracts signed, he may have been the single busiest actor in the history of SAG (the Screen Actors Guild)."