The most powerful Pokemon card in the world?

Well Arceus is the pokemon "god" but everything has it's own weaknesses. (except sableye and spiritomb)

Of course some pokemon are definitively tougher than others, it really depends on what you want in a pokemon, weather you want a wall like steelix, a sweeper like Gengar, something to set up an entry hazard like Forretress or just something to get your stat's up like Shedinja/Ninjask, basically it all depends on your strategy.