I agree with most posts here. You want a loyal dog and most will be loyal. I wouldn't get more than two dogs, as three or more is a "pack". Unless you and your amily can truly be alpha and beta, the dogs could turn. Even family dogs. That being said, it is easy to train a dog not to bark. It does take patience and time, but so does almost everything you do, that involves prepping.
I do like mixed breeds, as they seem to be more hardy - health-wise - than pure breds. I like the suggestion of volunteering at the local dog shelter. You get to have contact with a lot of breeds, and you get to know some good people. Don't believe them 100% on what they will "guess" a mixed bred dog is made up of. They often are way out in left field on their guesses. If you really want to know, ask a vet. Or a very knowledgeable dog handler. One who has a lot of experience with a lot of breeds. Just don't let the bleeding hearts know you might eat the dog, in an emergency/last ditch situation. You can even foster dogs for them, and get some great hands-on training experience. Just basic obedience is good starter training.
I recommend the book "How to be your dog's best friend" by the Monks of New Skeet. I got mine at 1/2 Price Books for under $6.00. That is a great way to learn of dogs' temperments, etc. I will look at home, at some other books that I really like also. When I want to learn, I get or barrow as many books as possible. That's me. But that first book is very good. Research a breed that you might want to get. I bought a book on pit bulls. I was thinking of getting one, but now am not so sure, after reading that book. Do your research.
My mean sounding dog is aging, and I really don't think he'd back up his bark anyway. I've been looking for another dog.
? Rescue Me! ? ANIMALS FOR ADOPTION ? Dogs, Cats & More is a good place to look, but again, they are full of s&*% on what they guess the breeds are, making up a mut. But you can sometimes find a good healthy, house-trained dog for free on that site.
Good luck. I have had dogs all of my life, and just couldn't live without at least one. Wouldn't want to. A good dog, that you spend time with every day, will be good back up for you, even if you think it's the most mellow dog out there. Oh, I would not get a mastiff, as their life-span is so short, they are heavy, so less agile, and if it came to them making a quick dash? Let's just say they aren't made for sprinting. Unless they are back-up to a lighter, faster dog. Then I'd think about getting one.
Oh, and welcome.