I would choose a toy poodle. I had an apricot toy poodle years ago and he was the best dog ever (shhh...don't let Jackson hear that
). They are so smart, easy to train, loving, loyal, etc. Everything that was said in that first post about toy poodles is so true! I love that they don't shed too. I guess I'd choose a Maltese for my third favorite. They are very sweet (at least my previous one was) and cute. They require more care than a yorkie or a poodle, however. Keeping those little faces white can be a challenge because of the tearing.
So are you thinking of getting a second dog that isn't a Yorkie?