I think the best overall site is
http://www.comparecanines.com . The beauty of this site is that like most others, you can check off the list of attributes you're looking for, and pull up the top breeds for your requirements. What they ofter next is best. You can compare the breeds you like, side by side, and they'll list everything from grooming to temperament to trainability to health issues. Overall, a great way to really get a handle on the specific breed that works best for you and your family.