I am adding the Rottweiler to the list of breeds to consider, and would love input from people who have lived with them. Is dog aggression a real problem? If properly socialized (think walks in busy places, accompanying kids on the way to school, doggy daycare, trips to the park, etc) is this still a real possibility? Activity level - as a work breed I know that they can go for hours on end. What I am curious about is if they NEED to go for hours on end. Would a couple of short walks a day, with occasional trips to the park be enough for them? I'm trying to be realistic about what I can provide. Living with young kids with friends, and a shih tzu - could a Rottie be trustworthy in this situation? My young children have friends coming and going all the time, so the puppy would obviously be raised in this environment. Do you see any potential issues here? I'd love to get all the input I can.