I agree that Clarice takes the cake. She is Mrs. Johnson. Like michael said, I was hooked as soon as she made her debut. There were very few characters so entrancing.
I find it interesting how the character of Mrs. Johnson is sort of the key in all of the various incarnations of the show. However she is written or portrayed is a reflection of the tone of each project.
Anyone notice how Clarice really fit into the original series? How her acting style and appearance enhance the stories and the other characters? Clarice's Mrs. J is a key ingredient that provides a balance between the quirky and the dramatic.
Similarly, the harsh and cold demeanor of Mrs. Johnson in HoDS accurately reflects the tone (and setting) of that tale. Clarice's Mrs. J would never have worked in the universe of the DS movies. It was too far removed from the homey, "claustrophobic" atmosphere of the original show.
In the 1991 series, Juliana McC was a perfect complement to that cast and the specific tone of that series, just as Ray Shirley was to Depp Shadows. In each project, Mrs. J manages to both encapsulate and reflect everything around her.