My favourite Pokemon of all time is Arcanine,because its a cross between a tiger and a canine which I personally find awesome. It has also been a great help in my Pokemon adventures, without it I couldn't of completed the game.
Another of my favourites is Reniculus. Who doesn't love a cute Pokemon that is made up of green blobs?
Aerodactyl for my favourite fossil Pokemon. It just looks badass also it's an amazing fighter. For legendary I'd say Mew probably but Latios is pretty close as well. Mew is adorable and powerful too in the first movie