Dogs are great companions. We have 2 mutts - both adopted because they needed homes bad. IMO that's the only way to get a dog.
One is a brindle 14 year old pitt-lab mix that we got when she was about 5 months old - the shelter that had her named her Bridey. She had been stolen out of someone's yard because she was severely neglected and tied to a tree. She had mange, whipworm, and a BB in her leg. She is one of the greatest dogs I have every had.
The other is some sort of a little poodle-terrier mix, about 12.5 years old. We picked him literally 1 week before we moved from southern CA. We were at the dog park with Bridey and someone dropped this dog off because they found him wandering without any ID and in sorry shape, and figured someone there would do something with him I guess. Well, my wife did something with him and brought him home. He was scared, of course, and we ended up having to take him to the emergency vet for a $200 visit because his ears so bad. We then had him cleaned up and feeling a little more comfortable with us, my wife named him Simon, and we decided to take him with us to Oregon. He sleeps right next to me every night.