Scooby Doo: Based on the popular cartoon by Hanna Barbara, Scooby Doo is a lovable Great Dane always in tow with his best Pal Shaggy as they and the rest of the Mystery Inc. crew solved crimes.
Marmaduke: Anyone who reads the newspaper funnies knows who Marmaduke is. Based on the antics of his real life past and present Great Danes, Brad Anderson's comic strip centers around a Great Dane named Marmaduke and the funny interactions he has with his family. Something most of us Dane owners live daily.
Astro (Jetsons) - Astro is the Great Dane in the cartoon "the Jetsons". Astro, is George Jetsons best friend and like Scooby-Doo can talk.
:taken from Wikipedia
Huff The Great Dane: Winner of the 2012 Super Bowl Doritos challenge. A fan submitted commercial picked out of 1000s was aired for the super bowl and won first prize. (The funny thing is most Great Danes would be afraid of the cat)