Hi, I am part of the saucon valley boxer club and I have purchased a dog from Erin's Boxers, they (Jack and his wife) are great people and are Part of the NJ Boxer Club or Eastern Boxer Club. Harley is 5 1/2 years old now and he is awesome!
One thing you have to realize when you goto some breeder sites is that 1) these people are usually older and not web savvy (ie, web pages are just to get their name and phone on the web, very simple, not fancy) 2) these people are old school so calling them rather than emailing may be better.
Stay away from greenfield puppies, they are a puppy mill. I would personally reccommend Erin Boxers, Connor is Harley's "Father" and Harley is show quality, but more importantly he is part of the family and is great with our 2 year old son and our other rescue boxer Bella, who is deaf.
feel free to contact me if you have any questions.