I don't have any non-chicken animals, BUT I work on a city farm . . .
I vote goats. Pigs are nasty creatures. I never would have thought that one sow could produce that much poo, smell that much, destroy that much ground or be that greedy. They are very strong, even the females, and could happily knock a grown man to the ground.
Goats, on the other hand, can be charming. There are two adult nannies at the farm, and we have just got 4x 5 day old wethers. They came from a dairy farm (they would have been killed at day old otherwise) and we are bottle raising them.
Although the nannies can (occaisionally) be a little bolshy, they are lovely really, and are generally quite sweet. The goat kids are the sweetest thing, and are getting to be really friendly.
And if it wasn't goats, then sheep would be the next best thing, as they are similarly sweet, if a little bolshy!