Arceus is my god. :)

[b]Favourite:[/b] I have 3 tops that I usually like to have on my team, but I'll go with Starmie. It's a Pokemon that can cover a large number of weaknesses with it's ability to learn water, ice, psychic and even lightning attacks. Add that to the speed and high special attack, and it's a fun pokemon to start a playthrough with (Yes, I hack one into every game I have as my starter).

[b]Worse:[/b] Porygon and all evolutions. I have memories of getting the insane amount of coins in Pokemon Red, only to purchase a crappy normal pokemon that was piss weak to many others. By that point I had a Dragonite, Zapdos, Haunter, Blastoise, Flareon, and Parasect that were doing quite well, and that artificial pokemon was not worth the time and effort!