I like both, but I am partial to cats. Funny thing is, the reason I like them is the same reason alot of people hate them - because they're independent. I love my cat because she clearly has chosen me over everyone else, and she isn't an attention slut like alot of dogs are. It may sound selfish, but sometimes it's nice to have a pet that you know is all yours. To me, there is nothing more soothing than a purring cat next to you when you're feeling down or sick or upset. And really, cats aren't the hateful bitches that people make them out to be. They can be every bit as loving as dogs, they just won't do tricks for you and play fetch (although my cat does XD).
And some of you people are being far too closed-minded about cats. Most of what you're saying is just generalization, and based on what you've heard rather than actual experience owning one. Dogs can be lazy and sleep all day (like my dad's wife's dog) just as much as cats can. Also, if you want a testament to cat loyalty, try my cat. If the dog or the other cat are being aggressive toward me in any way, my cat will run from wherever she is and get between us. If I am not awake and out of bed by 6 AM on weekdays for work, my cat will climb all over me until I am. When I leave the house and back out of the driveway, I can always see my cat in the window, watching me drive away and meowing. The second I step back in that door after being gone a while, my cat will be right there meowing and purring because she's happy to see me. She's 11 years old and still playful as a kitten, and she can sense my moods. She also comes when I call her, and sleeps at the foot of my bed every night.
So before you draw conclusions about cats, try owning one first. I live with both, I like both, but I definitely prefer cats.