Gen 1: Blastoise, Raichu, Nidoking/queen, Arcanine, Flareon, Dragonite
Gen 2: Furret, Xatu, Ampharos, Sunflora, Houndoom, Donphan
Gen 3: Breloom, Mawile, Swampert, Blaziken, Flygon, Gorebyss
Gen 4: Lopunny, Honchkrow, Togekiss, Leafeon, Shaymin, Hippowdon
Gen 5: Serperior, Stoutland, Whimsicott, Archeops, Hydreigon, Scrafty (it was hard to limit this one, as pokemonwise this is probably my favourite gen. Yeah, even Garbodor and Vanillite. Screw the haters)
Gen 6: Florges, Goodra, Delphox, Chesnaught, Greninja, Furfrou, Vivillon (Another hard one. I like all of them)
Really though it'd be faster to list off the pokemon I don't like. I can at least find merit in most of them.
Its really hard to just pick one. But, right now, there are 2 that are in competition for "favorite"
Gardy is obvious. Whenever anyone thinks of monsters, they always picture scales, big teeth, sharp claws, tentacles, puke green color, etc. But I've always been enthralled by the notion of a monster who, while being incredibly dangerous, is extremely beautiful, with elegant/feminine looks and flowing elements. When the beauty of the beast is part of what makes it dangerous. From the Sirens, to Harpies, to Succubus, it is always more engaging when the monster you face is far prettier than you. To add on top of that, the idea that Gardevoir actually is an eldritch abomination in disguise only makes Gardy that much cooler.
I normally hate inanimate object pokes, but Chandelure breaks that mold with a railgun. That whole blue candle afterlife thing is something I've seen in many places, and being a ghost fire, this actually makes sense of Chandy to take on the shape of an inanimate object that holds and maintains fire. So it isn't one of those "WTF a key ring? really?" pokes. To top it off, the object being imitated is a chandelier, which is a really awesome object to begin with. Should a real life chandelier turn out to be a spirit out to eat your soul, it would be legitimately terrifying. So, his design is cool, his concept is cool, he does cool stuff. Its hard not to like him.
Rest in Peace City of Heroes: April 27, 2004 - November 30, 2012. We will miss you. Cause of death: "Realignment of Company Focus" by NCsoft.