I'm sure our raid leaders and a lot of others know this stuff by heart, but I never bothered to learn it. The information for the following links was pulled together from a number of sources so please let me know if you see any problems. The gear and weapons information I gathered from looking at the top one or two players in each class and specialization on Wow Heroes for Alexstrasza. Sometimes the gear and weapons can be personal choices or just what has dropped for the particular player. Anyway, for what it's worth:
Raider Classes and
Raider Roles.
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