I'd like to say I like both equally, but I definitely have a strong bias towards cats. I like dogs a lot too, especially very big ones, and love playing with those of friends and relatives, but I don't think I'd ever want one for my own over a cat (or most other pets, for that matter). Cats' whiny meows and door scratching, or insistent bird calls can be annoying, but none of them have that grating loudness of most dog barks. I could sleep through my cat or parakeets raising a fuss, or even drown the noise out with headphones, but dog barks are something else. Cats on the other hand purr, one of the nicest sounds any pet can make, so extra point in their favor on the noise front.
I like the outdoorsiness of dogs and how you can take them on hikes easily, but outside of my days off it would just be too much maintenance I can't afford to give. Also, the kind of dogs I like don't do well in small apartments. So cats all the way for me.