Hands down, my favorite breed would be shih-tzu. They are smart, loyal, confident, and laid back. It's almost amazing so much self importance can fit in such little bodies! We have 5 shih-tzu dogs and they range in age from 1.5 years (two brothers) to 10 years.
I also really like collies. We live on a small farm and have a blue merle collie we raised from a puppy. She is a very good farm dog and excellent protector (us and the horses).