It's considered a sin in some circles to name a sprawling corporate behemoth the best of anything. But PetSmart defies this prejudice. Its warehouse-size stores offer one-stop shopping for birds, cats, fish, reptiles, and the most loveable species to ever walk this Earth, the mighty canine. Its wares range from everything from dental care to food, aquariums to bird feeders. There's also grooming, training, and doggy day camps. It's not uncommon to encounter a rotating selection of rescue animals waiting to permanently decamp in your home. Its charitable arm helps rescue 400,000 pets in North America each year, and 90 percent of what you donate goes directly to animal care, one of the highest ratios in the nonprofit world.