"I Love Lucy," the classic sitcom starring real-life married couple Lucille Ball and Desi Arnaz, has been voted the best U.S. television show ever. Coming in at No. 2 on the "20/20" special "Best in TV: The Greatest TV Shows of Our Time" Tuesday night was "M*A*S*H," followed by "Seinfeld" at No. 3, "All in the Family" at No. 4 and "Cheers" at No. 5. "ER" topped the list of greatest drama series. "The Twilight Zone" ranked No. 2, "The Sopranos" was No. 3, "The West Wing" was No. 4 and "Mad Men" was No. 5.