If you want to play the latest expansion, you have to have all previous expansions installed. In order, these are:
1) The Burning Crusade
2) Wrath of the Lich King
3) Cataclysm
If you have Wrath of the Lich King installed but not Cataclysm, you can only level to 80, do not have Worgen or Goblin options to make new characters, and cannot access the Cataclysm zones (Hyjal, Twilight Highlands, Deepholme, and so on).
Otherwise, the game works just fine and you can play all content up to and including what was released for Wrath of the Lich King.
Note that the changes to the old world (Azeroth and Kalimdor) are changes to the base game, so anyone will have the new quests and dungeons from level 1-60, regardless of what expansions they have installed or not.
The latest expansion is #3 which is Wrath of the Lich King, and the latest patch is 3.4 (I think?) called Fall of the Lich King. If you want more info go to their website and they have all of those on there.
Wrath of the Lich King is the latest expansion pack for World of Warcraft. Coming soon, there will be another expansion pack for it called Cataclysm.
To get the Cataclysm expansion, simply upgrade your account. Note: To get the Cataclysm expansion, you must first upgrade to Wrath of the Lich King expansion, then upgrade to the Cataclysm expansion.
World of warcraft (original), The burning crusade, Wrath of the lich king, and most recent cataclysm
Playing Cataclysm requires you to already have installed World of Warcraft, as well as the Burning Crusade and Wrath of the Lich King expansion packs.
World of Warcraft Expansions in order are as follows: Burning Crusade, Wrath of the Lich King, and Cataclysm. As of September 25, 2012 the newest expansion Mists of Pandaria should be added.
There is no expansion Burning Legion. The expansions are (in order): Burning Crusade, Wrath of the Lich King, and Cataclysm.
Currently (in Wrath of the Lich King), it is Thrall. When Cataclysm hits the stores, Garosh Hellscream will become the leader of the Horde.
No you do not get all other expansions when you buy Cataclysm. You have to buy each and every expansion, in order, in order to upgrade Cataclysm. This means you have to buy the original game (which includes Burning Crusade), Wrath of the Lich King, and then Cataclysm.
Wrath of the Lich King is currently priced at $39.99 at Wal-Mart.
No, Once you have a client with patch 4.x you don't ned to install anything.
Most lvl ??'s are classified as lvl 83. They are a level equal to the maximum character level +3 (83 in Wrath of the Lich King, 88 in Cataclysm).