I have a yorkie/maltese mix and to be honest with you, I actually decided that he completed me so much that I chose not to have children!! He's extremely lovable and requires a good amount of attention. I work from home, so I'm able to provide that to him. He's an emotional dog who shows various personalities all the time from fear, to love, to excitement, to anger (he may growl if i try to move him while he's sleeping
).
I give him the puppy cut and I only need to take him to the groomer about once per month. I have a small fenced in yard and that seems to be more than enough for him for exercise.
I, too think it's wonderful that you are researching. Yorkies tend to be funny little dogs and you can train them quite easily, once you get past the stubbornness. I've trained Cooper to ring a bell to go potty, but I can't for the life of me get him to drop a ball when he wants me to throw it.
I'm considering another dog, and I'm definitely excited to get another Yorkie. It sounds like a great breed for what you are wanting. Also, my Cooper is 9 pounds, so he's not as fragile as the other little ones.