Depends on what your looking for, if you just want nice cute, fuzzy animal that you don't have to work with really, then I'd say a cat. But if you want an animal you can actually somewhat interact with I'd say a dog.
Had a cat from the age of 2 to 17...he didn't do much except eat, sleep, and rub up against me when he wanted petting.
Got a dog when I was 14, he ran up to me whenever I came home, he protected the house, we played games in the back yard..and he definitely was in sync with my emotions/energy..its almost like he knew when I was happy, sad, etc. Was also very friendly, especially towards children. My cat on the other hand didn't like anyone except me and my aunt lol.