My sister fosters dogs, mainly working dogs like kelpies and border collies. She's had about 40 go through her care in the last few years.
Her latest dog was an 8 month kelpie who was surrendered by his owners after they almost gave him to someone to be shot! He's now been living with us for the last week and he's an awesome dog. Blows my mind how anyone could think of shooting him.
We have another dog, a pure bred rhidgeback who's 8 that we did get from a breeder. When we got her we looked around a lot of the shelters to see if they had anything we'd like but had no luck. In future we will always adopt a dog.
All the shelters are crowded with dogs who have had a very tough life. If anyone is looking for a new dog then I'd urge you first to see whats available to adopt. Nearly every dog bread out there has adoption agencies. Giving an animal a second chance is life is one of the most fulfilling things you could do.
My sister fosters a lot of dogs from heard2homes. She also fosters golden retrievers from time to time but I can't recall the name.