My list goes as this.
Dogs
Horses, because they understand human body language and are the second smartest domestic animal
Cattle, very easy going, they like being around humans as much as the other two above.
Chickens, birds but especially chickens are very impressionable to their humans
Cats, because I had to include them. They enjoy attention and company of humans more than cattle and chickens in most cases, but they don't understand our body language as much as any of the above, and might have highjacked some of our brains with a parasite.