The title may be misleading - because my question was different!
Initially I was going to ask if Each Tank had a DESIGNED NICHE, which would be stable for the foreseeable future. Then I realized I only cared about the Druid vs Monk. ( I refuse to jump on the DK Bandwagon, and so my options are - Warrior / Druid / Monk)
If the raid already has a "Good" DK and a Pally on standby - which would you prefer to have as a 2nd tank - Druid, Monk, or Warrior
PS: I expect and hope to become primary tank.