Dogs! Anyone says otherwise is out of their minds. They're loyal, unconditionally loving, they heal and protect us, they don't judge or aren't critical, they'll give you a nuzzle even when you're grumpy are eager to play even when you've hurt them or hollered at them, they just instantly and totally love us back. They are our best companions, they practically live for us, nothing will ever revere you or cherish you like your dog. Richly diverse, culturally integrated around the world, for some of us they're family. Nothing better than a dog.
Chickens are a close second, but only because they're so important to our diet as birds and eggs. I have a lot of respect for chickens, and their noble sacrifice for my extra-crispy needs.
Actually being serious about that last part, I give real thought about the meat I eat and try to never waste it so the creature that died to feed me didn't die trivially.