I have never been a dog person, I have always been a cat lover. But if I were to choose I would say a toy dog or a Shih Tzu just because they are so cute, and I prefer the little small dogs to the big ones. I have only pet-sat a dog for about two weeks twice. One was a small dog, kind of looked like a Shih Tzu and the other was a very big dog. They both smelled even though I bathed them every day, I guess I needed a better shampoo, and the little one barked all night. The bigger one was a lot more calm and quiet. I can't say how they were in terms of intelligence though.