WoW: The Burning Crusade features Rogues and Shamans as two of the nine playable classes. Ever wonder what it's like for a Rogue to attack a Shaman in a non-stealth mode, deal with the damage, and knock him out? Might as well watch the video linked here featuring "Rogue vs. Shaman" to find out.
Rogues are a powerful class because they are able to move around (albeit slower) in "Stealth" mode. They can obtain valuables from NPCs and use a combo of attack strategies and weapons. They can also disappear in combat, but as soon as they get detected (they aren't 100% immune to it), they can be attacked, disabling their "stealth" presence.
Shamans are versatile hybrids: they are healers, mages, and warriors. They can cast spells and hurl melee attacks. They emerge from Horde races of Orcs, Trolls, and Taurens, but the Draenei are likely to play as Shamans in The Burning Crusade expansion.
