New Dog Dilemma

I have said already that in a few months when I move out of state that I will be getting another pup. I have to wait till I get settled and its killing me to be honest. I have thought long and hard about what I am looking for in my next dog. First off I this time only would like a female dog. The other thing that I struggle with day in and day out is where to get my pup from.
I am looking for certain things that I want in my pup. Things like heavy bone structure, sound temperament, certain color etc. So running off to a good breeder sounds so easy because I can find a breeder that has dogs that have all the traits that I desire. I figure some where with in 100 miles of where you live you can find pretty much what ever you want. The problem I have is I feel obligated to get a shelter dog. I know all to well how many amazing animals there is waiting for some one to take them home in shelters. I love the feeling of saving a life. I might not be able to meet the parents of a shelter dog or know anything about its past. So I go back and forth because there is just to many great dogs that need homes but I also have been dreaming of a certain dog that I have wanted for a long time. I could get really lucky and find the shelter pit bull that has all the traits and characteristics I am looking for, but if I don't then how long do I wait? How many shelters do I check? I really just don't know what to do but I will keep you posted. Leave comments if you have any advice. Thanks