Cats, because they rock. They're far superior to dogs in almost every way.
Cats are inherently intelligent. Only reason they don't wanna learn tricks is because they simply have enough balls to say 'Screw you, I'm not doing that crap. How bout you leave me alone and I won't tear your face off for insulting me by trying to treat me like slave'. Dogs are usually inherently stupid. For example, my mom's old dog (golden retriever no less, not some super ******ed small dog) never could quite figure out NOT to mess around with porcupines. Two or three times they had to bring that moron to the vet to get quills yanked out of his face.
Cats don't drool all over you, dogs do.
There's no such thing as a 5-lb cat that thinks it weighs 200-lbs and 'talks crap' by constantly barking at you despite the fact that you outweight it by 195lbs... Dogs: ever met a chihuahua, poodle, or any other moronic small dog? I've never met a greater candidate for being punted in teeth.
Cats crap in a box that's easy to clean up, dogs you have to follow around and clean up after (assuming you're urban. If you're in the country I guess it doesn't matter).
Cats just go outside and come back hours later. Dogs want to get let outside, then they're unable to make up their mind if they want in or out or in or out, and try to make you constantly open the door to make up for their inability to make simple decisions.
Cats are super tough pound for pound. My 8-lb Cat (outdoor cat) killed a 20'ish pound wild turkey (and those things are damn tough birds).