I would vote a dog that is/can be used to rabbits. It'd be a good playmate for the both of them.
However, like Lexi says, it depends on your lifestyle. In my experience, dogs also tend to need to visit the vet more often, and therefore cost more. But if you want to be more active, a dog is the way to go.
Cats are... well, depending on the personality, can be playful, but they also tend to stick to their own space for a while (unless they want to be close). Don't get me wrong, I love cats, I have two of them, while my mom has two small-ish dogs. We've had more in the past, but I love both cats and dogs equally.
I've also had a rabbit for a short period, and because you have one, I'll assume you have the time to care for it. So you need to think about that, as well.
My rabbit got along with one of our dogs, and the dog loved to play with it, but the others stayed away. I guess a major factor is how they act around each other.
However, like Lexi says, it depends on your lifestyle. In my experience, dogs also tend to need to visit the vet more often, and therefore cost more. But if you want to be more active, a dog is the way to go.
Cats are... well, depending on the personality, can be playful, but they also tend to stick to their own space for a while (unless they want to be close). Don't get me wrong, I love cats, I have two of them, while my mom has two small-ish dogs. We've had more in the past, but I love both cats and dogs equally.
I've also had a rabbit for a short period, and because you have one, I'll assume you have the time to care for it. So you need to think about that, as well.
My rabbit got along with one of our dogs, and the dog loved to play with it, but the others stayed away. I guess a major factor is how they act around each other.