Bob Newhart, you mean. Actually I would put that amongst the best series ending. Waking up next to Suzanne Pleshette and talking about the "dream" he just had, which was basically the entire run of the show, was totally unexpected (no internet to leak the ending back then) and really clever, IMO.
As for bad endings, put me down for Friends. The show was never as great as it was made out to be but the ending was incredibly lame.