Just to add to what mr. herriman said about adopting purebreds... Both of my dogs are purebreds, both were adopted. With our first dog, we worked with a phenomenal breed rescue -- the best thing about them is that they are so committed and passionate about the breed that they are really invested in finding the best home for each dog (e.g., first-time dog owners or people with young kids will be matched with a different kind of dog). So, it took a couple of months, but we got a dog that fit exactly with our lifestyle and was all of the things that seandr listed (intelligent, good temperament, a good watch dog, not too high energy). The only thing missing was the raising him from 9 weeks part, but, since he's basically the best dog on the planet, I really don't think raising him ourselves would have made any difference.
With our second dog, we were open to taking on less of an "ideal" situation, so we adopted a puppy mill mama who is a little more high-strung and isn't fond of strange dogs. But, the point is, for many breeds, it's totally possible to adopt a phenomenal dog from a breed rescue. Petfinder.org
is a great resource.