It totally depends on what you want out of a pet, and your living situation and time. Both make great pets, although with a dog the breed/mix is very important. Cats are more independent, but chosen properly can be extremely affectionate and bonded to their humans. Dogs are eager to please, so cats (because they are NOT dogs) are labeled cold and standoffish. Not true at all. Dogs require training - to not bark, to walk nicely on leash, and to use the outdoors as their potty. Dogs also require a more regimented schedule - a cat will wait for you to grab things at the grocery store or stop for dinner on your way home from work. A dog is waiting to go potty, and cannot wait for you to make a leisurely stop. Dogs are more expensive to vet - they go outdoors, and a cat does not. Some apartments allow cats and not dogs, others allow small dogs. Do you have time to devote to exercising/walking a dog? These are things you need to consider when choosing. We can't choose for you. I have (until recently) always had both.