In <raid prep>, the rank of "geared" basically means that your gear is sufficient to start running the first level 80 raid, Naxxramas. Your gear should consist of level 80 rares and epics from heroics or crafting. Shoot for the following stats to be considered "geared":

 

tank defense: 540

tank health: 25k
tank armor: 21k

 

healer spellpower: 900
healer MP5: 160

 

heroics dps: 1.5k (1350 SP or 2.5k AP, 7.5% hit)

 

A basic 10-man Naxxramas raid consists of 2 tanks, 3 healers, and 5 dps.