A couple people have asked about what nature resist I use for Anub'arak here and there. It's pretty easy, actually.
Nature Resist Totem (130)
Arcanum of Toxic Warding (25) - from Knights of the Ebon Blade Honored
Enchant Cloak - Superior Nature Resist (20) - farmed from Icecrown mobs. And the drop rate really isn't that bad.
Lesser Flask of Resistance (50) - pretty much any alchemist will have this, though it costs fireleaf, which isn't that common.
Fur Lining - Nature Resist (70) - farmed from the same icecrown mobs as above. This is a leatherworking-only perk.
Runed Ring of Binding (25) - Onyxia 10.
And while I don't have it, Signified Ring of Binding (30) is also awesome, and drops from Ony 25.
That's all it is. With the above enchants and flasks and totem, I get to 320 NR. Which is good for an average resistance of about 38%.
What does that mean for Anub'arak though? On our 2% wipe last week (side note: sob) this was my values for Leeching Swarm:
|Fellhoof ||1544848||16.2 %||214||7218.9||1544848||73||230926||214||1137968||2||2|
So I took 1.5 million damage from leeching swarm, and resisted 1.1 million damage.
Leeching swarm was active in this fight for 217 seconds. This is the formula for how much damage Anub'arak heals from leeching swarm:
healing = (damage done + absorbed damage)*(2.3)*(MS effect)*(player modifier to healing)
The MS effect corresponds to whether MS or wound poison is up - if it is, this all gets reduced by 50%. The 'player modifier to healing' is another example of awesome blizzard mechanics, where the player's talents that multiply healing done also multiply healing done to Anub'arak. So things like Purification or Master Shapeshifter (tree) boost healing done to Anub'arak.
The important thing to note here: resisted damage doesn't ever heal Anub'arak.
For me, that meant I was personally responsible for 1.983 million damage healed to Anub'arak - in 217 seconds, that's 9173 HPS. Yikes.
But how good was the resistance? The damage I didn't take was equal to 1.137 million/217 seconds or 5244 DPS I wasn't taking during this time. The healing done would be equivalent to 1.15 this value (MS effects were up), which meant that resisted damage was equivalent to 6030 HPS not done.
In other words, the resistance was the equivalent of 6k DPS done to the boss.
Note that this isn't all due to the enchanting this way; 130 NR provides about 18% resistance by itself, or about 3k DPS done by itself. That means the gear by itself contributed about 3k DPS, or 2.6k reduced damage.
That's very substantial, and it certainly makes it easier to heal the tank on the hardest part of healing.
Is this adviseable for other players? Probably not. Certainly not other DPS classes, who will already be fairly low on health and want to do maximal DPS prior to phase 3. Maybe healers, who may be able to take the hit on their healing power/regen power.
But almost certainly tanks. Our two tanks by themselves were responsible for about a third of all healing done to Anub'arak - and that was with me using NR gear. If I hadn't, we'd be closer to 40%.
So if you have enough health to survive the scary part of phase 3 - which is freezing slash + a melee hit + a leeching swarm tick - consider dropping it for at least a lesser flask of nature resistance.