I'm a bird person

so I'm going to recommend birds. If you get ONE, they tend to bond with the owner very well. There are several varieties of small parrots that are friendly; I have cockatiels and love them. We only had one at first and she was our baby, she rode on either mine or hubbys shoulder everywhere we went.
I think someone already suggested ferret too. They are playful and from the ones I've seen, usually good tempered.
enderfox: We were playing tennis once and a couple brought their pet goat with them. It was some sort of miniature animal and it was just like a dog; running after the balls and such. It was pretty cute.