Definitely not a Golden Retriever like the other person suggested. They have no protective instinct (they are very sociable), and still shed a lot even after using an undercoat rake, which should not be overused, because it can be damaging. Daily brushing is needed to minimize shedding, but it will never be close to low. They also have a distinct doggy odor. I bathe every two weeks and spritz on freshening spray almost everyday, but it still isn't completely masked. My Golden is lovely around kids & other animals, and is always eager to learn, but does not really sound like the dog for you, unless you are willing to vacuum more often. I've found that Labs, while short haired seem to shed even more.
I would suggest a Poodle; they are friendly & active (they like to swim like retrievers) dogs. They are also single coated, so they shed minimally, although you should take trips to a professional groomer for clips until you've mastered shears yourself. They are intelligent, and should be easier to train than some other dogs as long as you are firm, consistent, and provide positive reinforcement. Training classes still may be necessary, and I encourage attending them, to provide your dog with socialization and a training session with distractions. They are available in three sizes: Toy, Miniature, and Standard (#1 on Stanley Coren's list). The standard size (medium-ish) sounds right for you.
If you want a dog just for protection, the only guaranteed (and right) option would be to spend lots of money (in the ten thousands) on a properly trained one. Some dogs may defend their owners when necessary, some may flee.
EDIT: With allergies, you really need to get tested by an allergy specialist. All dog with hair have hair, and all dogs have dander. Even in lower amounts (like a Poodle), these factors may still trigger your allergies, which sometimes take awhile to appear.