LOL, a shot of a cat was one of my first captures the very first time I held an SLR.
I think it went something like horse, tree, barn, Cat, flower. All the major stuff was covered in my first 25 mins.
Cats,dogs, prized flower blooms from the back yard, a soda can closeup, a TV remote, a lens cap, a camera and or lens box sitting on a table, one's computer keyboard--ALL are well-respected, highly sought after subject matter for one's, "I just got my first d-slr!" post. The key is to take the photo soon after receiving the camera, and then uploading and posting it AS SOON AS POSSIBLE! And, extra bonus points for straight-out-of-camera size, something in the 4,358-pixel size on the long axis. Oh, and NO POST work on it either--that's triple bonus points!
You know I can think of far worse things to be taking pictures of than cats. Cats can be walking art, IMHO. Still I know what you mean. It seems nearly everyone who gets a new camera always takes pics of one of three things first their pet, their kid or some flower nearby. I probably won't have mine till December, if then, but I promise I'll do my best to find a first subject that's a pleasant surprise.