The most important thing in raising a dog of any breed is to start its training early. Especially if you get a German Shephard (or Dobermann or Rottweiler or any Bull Terrier/dog), as these dogs have very strong guarding instincts (the first three especially), and will require a lot of obediance training and exposure to other people/animals to ensure that they become sociable. However, trained correctly, Rotties, Dobermanns and Alsatians are exceptionally affectionate dogs, and are very good with children, especially.
As for Labradors, they
are the most popular breed for a good reason. Affectionate, strong, medium sized and don't require an exceptional amount of work. If you get a Collie, though, you'll find yourself chasing after it a lot...they're like pure energy in canine form (same for terriers).
Myself, I've always felt myself drawn towards the larger breeds. Rottweilers take a lot of training to make a good dog, but they are extremely affectionate if trained properly (contrary to what many people believe). Labs are a breed everyone likes, and I quite like Spaniels (Springer especially) as well. Do your research, and talk to whoever you intend buying the dog from...if you have any special conditions for a breed (such as low exercise requirement

), then they'll be able to help you.
The ironic thing from all this is that I don't actually own, nor have I ever owned, a dog.
