I'd suggest a Lab. I know, I know...but there's a reason they are so popular.
I agree you should go with an adult dog, or at least an older puppy, 8-10 months or so. Especially with a toddler and not a lot of dog/puppy experience, it would be easy to get overwhelmed with housetraining etc.
As for choosing the dog, try Lab rescues in your area. Also breeders will often have older puppies / young dogs that they were raising as show prospects, but turned out more 'pet quality.' Or were returned to them for some reason (not necessarily the dog's fault but maybe the owners moved, etc.) My aunt got one of these dogs, she was getting a puppy actually, but the breeder also had an 18 month old dog and she knew my aunt (an experienced Lab owner) would be a good home, so she got a good deal on the both of them.
Anyway that's my suggestion. And look for English labs, as they tend to be more mellow and laid back in my experience, while American bred Labs can have a lot of energy. My aunt's English Labs are constantly exposed to toddler grandchildren and cousins, and they are totally bombproof dogs.
If you have any dog shows near you, attending one can be a great way to see the different breeds in person and talk to breeders.