To me, a person's patronus is the animal manifestation of the person who watches over them. A very main example is Harry and his father. James was an animagus; his form was a stag; Harry's patronus is a stag - his father.
The wolf represents the person in my life that guards and guides me. He is passionate, cunning and loyal like the totem wolf. For more go here.

Plus a wolf would look kick-ass fighting off a dementor.