Really? In my opinion, them placing a dog as a pokémon was pretty thoughtless. You can notice the little effort they put into the fifth generation.
So it is kind of hard for me to name my favourite fifth gen pokémon, but I have to say I found several of them a little cute, like Whimiscott, Audino and Minccino. Oh, and Serperior. He was cool.
My least favourite have to be Cohagrigus, Tirtouga and Vullaby.