Unfortunately, television cats--at least outside of commercials--are less widely known.
Here are a few entertaining exceptions:
Kitty and Joel on The Closer
Brenda inherits Kitty, a female cat she continually refers to as "he," in Season 1. Kitty's demise and Brenda's grief are touchingly portrayed in Season 5. Brenda's husband, Fritz, later seduces her with the utterly adorable Joel, a new kitten whom Brenda continually refers to as "she."
Data's Spot in Star Trek: The Next Generation
Spot is Data's sometimes calico cat. Spot has as many adventures as her owner! She has kittens, transforms into an iguana/lizard-looking thing, and endures Data's experiments with nutritious supplements. She even inspires an ode!
Little Boy Cat in Psych
The 5th episode of Season 1 of Psych not only features a long-haired cat, its title references a classic cat myth: "9 Lives." Best of all, the cat ends up in a loving home with the sweet-natured Buzz McNab.
Mr. Boots in Dharma & Greg
In one of his finest roles, Teller plays a human-cat in the first season of Dharma & Greg. He is so convincing, even the level-headed realist Greg is persuaded to tickle his stomach, give him treats, and miss him when he leaves.
All these cats demonstrate that dogs are not the only pets to qualify as "an owner's best friend," even on television! From Brenda's Kitty and Fritz's Joel (co-opted by Brenda) to sci-fi Spot, cats can bring comfort, inspire poetry, help solve mysteries, and always, always entertain.