Ah, this is a difficult choice for me. As for in game, I tend to lean towards having more canine characters, but the ones I enjoy making the most are the feline ones. I love all of the neat patterns they have, while still being realistic. Plus, I've always been more of a cat person. Haha I had eight cats at one point!
For specific species, my favorite canine is not really a canine but a canid, and its the African wild dog. For felines, my favorite is the snow leopard. They're fluffy spot kitties!