i vote cats, simply for the reason that if you work (which i'm going to assume you do, or are atleast out of the house for a good chunk of the day) they can take care of themselves for the most part.
food, water, litterbox, and you're good to go. if you get a kitten you WILL need to housetrain it and it 90% of the time will defecate elsewhere in your house, but that's just like any free roaming young pet.
once they're trained though, you don't have to worry about the kind of stuff you would for a dog, as they're very independent. just need to show it some love when you get home and it'll be loyal forever.
