The best breed match I have found is on animal planet
You can complete the questionnaire to find the breeds that best match you, your family and your lifestyle.
There are other links on the site which have information about all breeds, dogs that make best pets for families and much more. As with all animals, the breeds are an indicator of the animal and its personality, but a lot depends on every individual animal. Always meet with the animals before deciding on adopting.
Once you narrow down the breeds, you can find them on http://www.petfinder.com sorted by your local area.
Half the shelter animals these days are pure-breeds. So if you do want a particular breed, you can be sure to find a lot of choices. Most of the other dogs are usually mix of 2 breeds and not really mutts. Mixed breed usually tend to have less health problems and better temperaments!