I have always been SO torn on this!
Regarding real animals, both wolves and foxes are among favorites. In fact, they ARE favorites. Mostly because they are both in the canine family. (And all animals in said family are among favorites.) And they are definitely at the top of the list, only under the domesticated dog.
Regarding Pokemon, Fire types are a big favorite. Only one I favor more are the thunder type. They're both fire types, obviously...
I've never been able to choose a favorite. BUT since you can only vote for a poll once, I think if I had to pick... I'd say Arcanine. I usually go for the cool looking Pokemon if I go based on looks and not anything else. And since they're so similar in every other aspect, it would boil down to looks. Ninetails is more "elegant" and Arcanine is more "cool" looking. So... yeah, Arcanine.