I had two wonderful cats for many years and then a dog. I was of the "cats are better than dogs" persuasion until I got my golden retriever. She's such a wonderful dog, so intelligent and a joy to play with that I can't really say that.
Cats and dogs have their pros/cons. I don't like the notion that cats require less attention, because they really don't. It's just a stereotype that causes many people to ignore their cats. My cats were always around me, always wanting to play and wanting attention.
And to those that say dogs are dirty, I don't see how that's the case at all. We keep our dog clean, and she most certainly doesn't drool. My cats also shed far more than my dog does. As much as I love my cats, the litter box can be pretty nasty at times.