Now that I work in a shelter, I have to say : Shelter. Our animals are all lovely, getting well with othre cats an dogs, they are great with other people as they are used to see visitors and stuff. For sure, my next animal will be from there.
I used to volunteer at a shelter too! I really loved the atmosphere there, everyone is so caring and they really teach you how to handle every type of animal. It was a stark contrast from my cousin's experience - she used to work in a pet store and the way they taught her to treat animals was kind of appalling; they still believed in the dominance theory, and she learned to like hold her dog down by the neck to "assert dominance" if he misbehaved, stuff like that. :s Really stupid, I'm glad they're no longer in business.
One of the pet stores in know does a thing where they bring in cats and whatever from the local shelter to help get them adopted. That's probably the best situation possible because not only do you help free up some space at the shelter for a while, but the animals get more visibility and there are ample supplies right there for you to get so you'll have all the basics covered.
I know Austin's (user: revenant here) cats were also from a pet store that had an arrangement like that with a local shelter, and I've been seeing that more and more over here as well. And I agree - I feel like a lot of people go to pet stores instead of shelters because there's some stigma with shelter animals, that they're abandoned because there's something wrong with them, or they don't want mutts, etc. But I think once people actually see these animals and see that they're not so different from a 'brand-new' puppy/cat (maybe even better in some cases - there's a lot of horror stories with pet mill animals), they would consider adopting instead of buying. So it's good to have them in pet stores from time to time for more visibility, like you said.
Another question for everyone, are pet stores still popular where you guys live? They've been slowly dying over here (the ones that sell dogs and cats anyway), and I think it's because people are more and more aware of pet mills these days. The SPCA managed to get one of the cities around here to approve the ban of selling puppies - it was the same city with the pet store that employed my cousin, and they went out of business shortly after the ban because they heavily relied on puppy sales for most of their earnings, and since then the entire chain has been dying off even in the cities where the ban isn't implemented, because people are more aware of the conditions in which they kept their animals.
But yeah, not all pet stores are bad - there are large chains that don't rely on live animals to thrive, like PetSmart.