I've realised that, when playing Pokémon, the trick to winning is to evolve your Pokémon.
This takes a bit of luck, in that you have to have the first level Pokemon on the table, then you have to have drawn its corresponding first evolve card, and then you have to have drawn its second evolve card.
So, if I want to create the ultimate Pokémon deck, I'd simply buy 5 water type decks, then assemble a deck containing 25 Totodiles, 10 Croconaws and 10 Feraligatrs. It would make for a less interesting game, but I'm guaranteed to evolve my Pokémon, and my opponent doesn't have a chance unless he does the same thing I do.
I wouldn't be the first person to have thought of this. Is there an official rule specifying the maximum number of any one Pokémon in your deck?