I have two Australian Shepherds and there is nothing better than coming home after a long stretch on the road or late at night and having them greet me at the door as if nothing in the world is more important to them than me coming home. Unconditional love, that's what dogs give us.
Cats are great for sitting on the couch and petting, though dogs can be just as useful in the petting department, but its dogs that look to us and ask nothing in return.

My cat owner friends always say that dogs have masters and cats have servants. I'd say that dogs have friends.

Dan