Voted for Dog.
It does depend what you are looking for. Dogs are with you the whole time. Cats are more independent so suit people who are out all day (if the cat has a catflap and access to the outside world. We are home based so the dogs are great, and you have to take them for walks even if the weather is dreadful, so you get fresh air and exercise as well as love!
I am with you on this one.