Best 1970s Sitcoms

After the reality of the "Network" news coverage of the Vietnam War, television had dropped censoring standards to allow those stories to air. The unintended consequences to that softening was the "Entertainment" divisions at those same networks world-wide saw it as an opportunity to push the boundaries on content. This started in 1969 unofficially. What was your favorite of that era on TV?

Note: The 1969-1970 Season began Sept of 1969.

After voting, please discuss here.