Now you may be thinking "There's tiers in Pokemon?" or even "What the heck is a tier?", so first off let me answer those questions.
What the heck is a tier?
Tiers are an attempt by players to classify characters in a game by their competitive ability. They can be found in any game with variable characters, including Street Fighter and Pokemon though they are most prominent in Fighting and Strategy games.
The existence of tiers can be controversial as skill usually has more impact on the outcome of a match furthermore there are constant ongoing debates over which tier each character belongs in.
There's tiers in Pokemon?
Yes, as with most strategy-type games there are tiers in Pokemon. Pokémon currently has a large amount of critters with various different stats and movepools. There are currently six tiers with various fansites individually deciding the Pokémon assumed to be in those tiers, most notably Smogon. Pokémon tier lists are prone to heavy criticism because there is no "official" tier list for Pokémon. However, official tournaments often have ban lists.
Okay on to the tier of the day.
So we're starting with the most common tier used in Pokemon competitvely play. Many people believe that OU Pokemon are the strongest in the game however this is a common misconception. In actual fact the Pokemon in the OU tier are merely the most commonly seen Pokemon on wi-fi, nothing more.
Examples of Pokemon in the OU tier include:
For a list of Pokemon in this tier, please visit: http://www.smogon.com/dp/tiers/ou