I like PetsEdge.com a lot too, or is it PetEdge.com? I ordered a bunch of stuff from there when I first got my puppy. They require a minimum purchase or they charge you a service charge, which sucks since I only have one dog. It's great if you are a breeder or have a pet supply store. I really like DrsFosterSmith.com a lot too.
It all depends on what kind of products you're looking for, but a few of my favorites are: kingwholesale.com; merrkickpetcare.com; petguys.com; jbwholesale.com; dresslersdog.com; sitstay.com; barkindogclothes.com; just to name a few.