I like them both.
I like dogs because they're just awesome. My parents breed Australian Shepherds (not show ones, actual working ones) and they are just the smartest dogs ever. It's amazing watching them work cows, sheep, ducks, and other animals and the intelligence they have. It's also pretty amazing them even work with children. They're protective, loving, smart, and everything you need in a pet. They also have Great Pyranese too (big white dogs that think they're sheep) and they're just huge, protective, and smart.
I like cats because, well, they're awesome too. With cats, you have to earn their love and respect. If your cat likes you, it loves you to death and if the cat doesn't like you or you don't like someone, that cat will hate you or that person. I had one cat who loved me and only me and anyone close to me she would claw their stuff, pee on it, or anything else to only their stuff and not mine (she even knew things in common places like the living room whose was whose).
If I really had to make a decision I would have to say cats. They just have so much more personality than dogs.
