The Icecrown Citadel raid buff has been out for a week now. For the time being, it's only a 5% buff to healing, health, and damage (and let's not forget that it will affect damage absorption spells soon). It'll continue to slowly ramp up as time goes by. I know the question I've asked myself is whether or not we should have the buff active for progression bosses. There doesn't seem to be an achievement or any incentive to take down bosses without it so it becomes more of a question of "Why not?". When we were working on Blood Queen the week before the buff was up, we've had some extremely close shaves where she hit her enrage timer at 6%, then at 2% before we killed her post enrage with 6 players still standing. That 5% damage would've easily given us some extra breathing room. Cutting through trash and taking down the early wings with the buffs up means we can cut through that stuff faster and get to the hard bosses earlier. So I know for me, I'm okay with working on bosses with it up. It's only 5%. Now I just need to figure out where to draw the line.
How about you? Have you been disabling Strength of Wrynn or Hellscream's Warsong for your raids just to say that you can do the bosses without it?