When I was first introduced to Pokemon as a kid, my favourite was Pidgeotto.
I mean, duh. I love birds, and it's a fierce, colourful bird. I was actually sad that it evolved further, because as neat as Pidgeot looks, I do miss the pink feathers...
Currently my fave is Skarmory, and I'm still not sure if it's because it is badass in general, or because it combines my two favourite types.
The design is damn cool, and I adore the shiny form! I have a thing for those copper-looking shinies.
Which is also true, amusingly enough, for my current second favourite, Klinklang.