This is Maddie. Having a dog gives you a great excuse for excercise–a couple of long walks a day is every bit as good for you as it is for your dog. Studies have shown that walking a half hour a day has a ton of health benefits. Also, there are psychological benefits as well–dogs are lousy conversationalists, but great listeners.
Adopt a dog from your local shelter. Then try to be as good a person as your dog thinks you are.