Since you are getting your puppy from a reputable show breeder, she will be able to advise you which puppy's personalty fits your "perfect puppy" image since she has spent so much time with the puppies. It's so hard to tell from one visit. A friend chose her Maltese puppy because she was the calmest and most cuddly when we went to visit. Tiffany must have been very sleepy when we saw her because she grew up to be a hyper, constantly barking adult with separation anxiety.
The Puppy Appitude Test is also helpful:
Volhard Puppy Aptitude Test