I agree with Giselle sooo much goes into picking a breed. I suggest writing down all of what you want (energy level, age, coat, size, personality, temperament, patience with kids, trainability, purpose) and searching through local shelters to find the perfect dog. Since you obviously aren't partial to any breed, just personality, a pound puppy sounds perfect !! It'd be best probably to adopt an older pup to adult (12 months and up), so you already know their personality and how they fit in with your 2 current dogs. Adopting an older dog is SO much easier also, you won't have to go through the horrible puppy stages. There are countless Rotties, Dobies, Mastiffs, Pitties, Labs, Goldens, Boxers, etc in shelters everywhere that need a loving home! Because you don't seem very active, consider adopting an older adult over 3 years old, that doesn't require a ton of exercise.