#1 sexiest is is Gretchen Corbett, in the bikini, in "Exercise in Fatality". 2nd place is from "How to Dial a Murder": Dog Trainer Tricia O'Neil also has a smoking-hot body sans bikini).
Top five remains constant for me over the years. #1-Janet Leigh #2-Barbara Rhoades #3-Gretchen Corbett #4-Mariette Hartley #5-Joanna Cameron