It's really impossible to pick out the best ad campaign of all time. Of course we would all say the original VW bug campaign is in contention. I might add that the "We Try Harder" Avis campaign is one of the best. Both created in that magical time at DDB. As great and successful as they are both, DDB also created the Levy's Rye Bread campaign in the 50's, "You don't have to be Jewish to love Levy's real Jewish rye" Levy's became the biggest selling rye bread in NYC after this campaign, and in those days we had those great Jewish delis on every other corner. No small feat. If you lived in New York, it was in the kitchen.
Judy Protas the copywriter, who wrote most of the Orhbach's ads for DDB, and Bill Taubin the art director, created those ads and posters that became a fixture in the city and have become iconic images. Howard Zieff was the photographer. Not many ads can stand the test of time the way these can. We have one framed in our office at The One Club.