I've never had a very intelligent lab. Lovable and loyal to be sure, but never very smart and therefore, for me at least, very difficult to train. They were very active as well.
The two rotts I've had were both very destructive. They were fiercely protective and excellent guard dogs, however, they are very aggressive and might not be such a good idea with other animals or children. These two were of average intelligence and very stubborn which made them very difficult to train. Maybe this is indicative of the whole breed; I cannot say.
I can however, highly recommend the German Shepherd. I have had excellent experiences with this breed. Very intelligent. The males were easier to train than the females. I also noticed that the males were more protective over the area and the females seemed more concerned with the family.
You specifically mention training....It is important that the dog be trained. Especially if you decide to go with a bigger, more aggressive breed. Especially if you choose to throw another puppy or a child into the mix. I would also re-consider getting two puppies. It is difficult enough to train one; 10x harder to train two in the same household.
Whatever choice you make, raising and training a dog is difficult and requires a strong owner. I would like to emphasize what Lurkette said about the dog understanding it's place in the household. It is imperative that the dog understand who is in charge, in this case both you and your wife. It's difficult to get male dogs to understand this (he will see your wife more as an object to protect rather than an authority figure.) The more aggressive the dog is the more difficult it will be.
There are a lot of things to consider when deciding to get a dog. A lot of perspective owners just don't do their homework. Fortunately, there is a lot of information out there available.
Good luck
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Ahhhh. Another thread killed. There are so many threads to kill, but it's really a labor of love, so I don't mind. I get a gold star sticker.....tee hee....