Don't get how most of you do your Unholy specs without going for Lichborne, realy.
Unholys whole tanking lies mostly on your bone shield, the more you can keep that active on you the better. Popping Lichborne while having an active Bone shield up effectivly increase the time your bone shield is active and lower the "gap" you have from the time that your current Bone sheild goes of till you can reapplie one.
Ontop of that, getting 25% more avodiance for 15sec is masive! Also worth saying that while under the Lichborne effect, you can heal yourself with DC.
This is my unholy buid, that have worked verry well for MT naxx so far: Talent Calculator - World of Warcraft
Few thought i'v been pondering about tho is for one bladed armor vs. Desecration. What's best for tanking. I'v been doing some small tests but need more looking into it before i can say for sure. Maby anywon else have done some testing and got a good awnser to this question?
About Magic suppression and AmZ, alot of mixed feelings about these talents. Personaly i like them. first of cause i like to know that when i pop my Anti magic shell that i'm completely immune to all magic damage for that duration, gives a nice feeling of safty in this "OH SHIT" CD. The extra 5% lowerd magic damage is also nice and will overall in long fights that consists of magic damage ( witch most does these days ) save some mana for the healers, witch is allways good. After going these 5 points in Magic suppression you naturaly go for AmZ aswell, i'm a fan of the ability, first of for beeing able to "shield" your healer or raid in realy bad situations or as a second ability to lower damage from high magic abilitys hitting you, sutch as breaths and things alike.