I was just about start a new thread about cat vs dog.
But then I saw all these threads about the same thing, so I'm replying with my own IMO:
I believe it depends on a human as to who that human prefers: cat or dog.
For me naturally it's cats that are the best persons to share my life with.
But I like dogs too (I have 2 of them).
The reason I prefer cats is that they are unlike dogs will not wag their tails for attention and will not lick you and get under your feet any time you come home.
Cats just seem to be more mature as persons and more understanding to my moods.
And yes - I'm half-disabled person physically, so I couldn't walk a dog and I don't want myself being licked if I don't want to be licked.
If cats show affection to me - this is really special and because they really mean it, not because they are meant to do so as species.
And cats are so very clean - I enjoy any time they choose to kiss me in their own way - that is so very special then.
And for the last, but not the least - cats for me are such independent and their attention means much more to me than that of a dog.
To say the least - when it comes to the security - my cats alert me to the true danger, whilst the dogs bark for nothing most of the time.
And in two occasions I have avoided a break-in into our place due to my cats jumping at me in the night and growling, whilst dogs didn't even bark once in those occasions.
Well, not to mention that my boy-cat is a real scare to all strangers entering our house, and my two dogs are not.