Wow, great comments from everyone, thanks. To give you a little more info. about my background, I've owned dogs all my life and 3 GSD. One when I was a child and two as an adult.
My last dog passed away a couple of months ago at age 12 and was a fantastic dog with a really interesting mix of drives - but who also had some issues.
As far as my experience as a trainer - guess I know enough to realize how little I know. I trained in Schutzhund for about a year and a half with my last GSD and got a BH. We were working toward a Schutzhund 1 when my club kind of imploded and I became disillusioned with some of the political infighting and personality clashes that developed between some of our members. But I do think I learned a lot from our training director and some of our members, who were very experienced and knowledgeable about dogs in general and schutzhund in particular. Our club also had a number of K9 officers, so I got to see a wide variety of dogs with varying abilities and temperments.
As a result I do have a pretty clear idea of what I'm looking for in my next dog and think I will be able to articulate it pretty clearly to a breeder.
I also know what I want to do with the dog - no schutzhund this time, but a lot of obedience and possible SAR.
My concern is that even hobby breeders want to find good homes for their dogs and are proud of their breedings. I'm concerned about going to two different breeders, whose dogs possess very different qualities and being told by both breeders that of course my dogs would work for you.
At the same time, I recognize that there has to be some level of trust between me and the breeder, particularly since even within a specific litter the pups are likely to possess a wide range of temperments and to some extent I will rely on the breeder to match me up with the best puppy.