The Sarah Jane Adventures

Sarah Jane Smith was Doctor Who's companion back in the mid-70's and remained a Doctor Who favorite and was brought back for appearances over the years. Her last appearance was in the final David Tennant episode on New Year's Day 2010 (see photo below). 
The Sarah Jane Adventures was a Doctor Who spinoff targeted at a younger audience but enjoyed the same high production value as Doctor Who and certainly wasn't "just a kid's show". 
Of course, there was only one Sarah Jane and that was Elisabeth Sladen who passed away last April bringing the story of Sarah Jane to an end. The final series, cut short by her death, was aired 6 months after her passing.
http://en.wikipedia.org/wiki/The Sarah Jane Adventures