I have always loved dogs too - well, actually any animal. Horses were my favourite animal for years, but I was younger then. I think cats are just easier for me, now that I can't always be there for a dog, or be strong enough to work with a horse. Cats sleep a lot and don't mind if you have to go out and leave them alone. They don't get all clingy - although my youngest cat does like to sit on my lap at night and sleep on my bed.
When I was younger, I had a beautiful Afghan hound and she was a lot of work with all the brushing and caring for her ears etc. So I think that dogs are just more like children, they are needy. True, they do love passionately (not unconditionally, I doubt there really is such a thing as unconditional love), and they are great companions. But since I am limited by how many animals I can have (I rent) then cats are just simpler.