Cats are extremely popular as pets. They are also beautiful, fluffy and affectionate, but a lot more self-reliant than pups. Most cats can be kept alone all day (or even over night) without ill-effect. Cats tend to eat less that puppies (with the exception of the toy variety of dog), plus they don't require twice daily walks, interval training, or constant guidance. Felines and kittens are a breeze to house-train, too. Just give them a litter-box and some litter saved in a peaceful area of the cellar, and you may rest assured your kitten will litter coach itself.
Finally, cats shed - sometimes a lot. If you are a nice freak, this can be something you would not appreciate. So if considering a kitty or kitten for your dog, be sure to take into account whether you are designed for cleaning the kitty litter box on a regular basis, vacuuming a whole lot, and working with the probability of furniture harm.