Male or Female?
You also need to decide whether you want a male or female dog.
Depending on the individual breed and its characteristics, males are often a little more protective of their property than females and, as puppies, tend to be more destructive.
Females are usually a little easier to housetrain, although males often take to obedience training better.
Although some breeds may have a little bit of difference, as a general rule there is no difference in levels of excitability, behavior problems, or affection between males and females.