The film Cats & Dogs[?] postulates an ongoing war dating back to ancient times between cats and dogs. The main character, a beagle named Lou, is voiced by Tobey Maguire, later better known for portraying Spider-Man.
Devil Dog: The Hound of Hell, from the film of the same title
Rin Tin Tin, first dog star, a German Shepherd found in a trench by an American soldier, has appeared in films since 1922. All subsequent dogs in the part have been descendants of the original. Also on television.
Wishbone, the eponymous Jack Russell terrier star of a children's educational series featuring literary themes and their application to issues faced by young viewers
"That Doggie in the Window", the waggly-tailed subject of the price enquiry in "How Much is That Doggie in the Window?". (Popular song by Bob Merrill, 1953, recorded by Patti Page[?])
The escapees in "Who Let the Dogs Out?" by the Baha Men