Hey yall. I've been testing specs extensively and researching just as much. I believe I have two specs that get the job done very well. In no particular order, here they are.
2h Blood.
http://www.wowarmory.com/talent-calc.xml?cid=6&tal=23050205300033032212230013510000000000000000000000000000230130305003000000000000000000
Rotation:
IT - PS - HS - HS - DS - RP DUMP
DS - HS - HS - HS -HS - RP DUMP
*if you want to help your raid group and get Abom's might up immediately you can move DS up to the front of your rotation.
Glyphs:
Dancing Rune Weapon, Dark Death, Death Strike
Rune enchant: Fallen Crusader
Note : This spec scales very well with gear and raid buffs/abilities. When I had the rotation down I was doing 4.7-5.2k dps last night in 25 emalon. When you pop dancing rune weapon, pop hyteria just before it. Its up every 90 secs so use it early in the fight. This spec benefits greatly from having armor penetration.
2h Unholy
http://www.wowarmory.com/talent-calc.xml?cid=6&tal=23050200000000000000000000000000000000000000000000000000230230334003215003150203133151
Few Spec notes: You can play with the points here to suit your needs. If you have the t7 set bonus you don't need dirge. If you do need dirge, take the points out of necrosis. You may wish to spec into Dark Conviction in the blood tree instead of necrosis. That is up to you. UPDATE* DO NOT SPEC INTO IMP UNHOLY PRESENCE. 0/10/61 is also a good spec, may even be better.
Rotation: The unholy rotation is more of a priority list.
Put up diseases, if diseases are up, blood strike to convert blood runes into death runes. Then Scourge strike as much as possible while rune dumping to prevent rp capping and filling in downtimes. Make sure to keep converting those 2 blood runes to death runes after youve used them. The whole idea is to use SS as much as possible while having diseases up on the boss. With the SS glyph, you can sometimes go a long time just using SS and BS(to get death runes to use for more SS). Keep an eye on your diseases and make sure they don't fall off. If they do, put them back up with IT and PS. Don't try and put them up with the SS glyph.
so the rotation usually looks something like this.
PS - IT - SS - BS - BS - RP DUMP - SS - SS - SS. Then you continue using blood strike to convert death runes and scourge striking to you hearts content until your diseases fall off. Fill in rune downtimes with RP abilities. Do not let your RP cap.
Glyphs:
Scourge Strike, Dark Death, Glyph of the Ghoul.
Note: I haven't tested this spec in 25 yet but it did well in 10 naxx. If you gear is not so great, this is your spec of choice.
2h Frost. I had high hopes for 2h frost and it was looking good in the ptr. It also does extremely well on the target dummy. I was pulling 3.2-3.5k dps on the dummy with it. However, it does not scale very well at all. Therefore 2h frost, as of now, will be behind Blood and Unholy. I will go further into this spec upon request but for now i'll leave it blank.
DW Can't compete with 2h blood and 2h unholy is what I have been reading all over the net. Don't pass on those one handers just yet though, with all the QQing about it im sure it will be back soon.
Minor glyphs for all specs:
Pestilence, Raise Dead, Horn of winter is what i use.