Remember this is still a work in progress as you read it please....also the ones that say "in progress..." I have the info for but ran out of time to post it today
Combat Stat Priority:
The forums say this is about the stat priority for Combat: Armor Pen > Agility > Crit > Hit (below poison hit cap) > Expertise > Haste > Hit (above poison hit cap) > AP. Remember this stat priority is just a guide. The overall combination of your stats is what is the most important.
Now that being said I'm sure some of you are wondering why I do things differently (non-cookie cutter) and by that I mean that I pretty much try for my current crit cap after I reach the poison hit cap and expertise cap. There are several reasons: I really like to take advantage of the Sinsiter Strike Glyph so I generate combo points faster, like to take full advantage of Prey on the Weak, prefer using Maces (though swords with a high dmg range work well too) which when spec'd into currently have a lot of Armor Penetration which makes Crit that much more important, one of my trinkets depend on critical strikes to give me the AP buff, and finally what I do seems to work according to the damage meters. In order for me to make this work I really have to be paying extra attention to my combo points since I can generate them faster and don't want to waste them by using Sinister Strike when I should be doing a finishing move.
Hit Rating Caps:
Since WOTLK came out the amount of a combat rogue's damage from white damage was lowered and more damage comes from poison attacks than it used to. The amount of hit needed went way down to what is called the poison hit cap (point at which poisons will no longer miss).
Assuming you have 5/5 precision (which every talent build should now), you want to keep your hit around 315 which is the poison hit cap at level 80 with 5/5 precision. If you are in a raid with a druid that uses improved fairy fire or a priest that uses misery on your target then that drops to 237 which is probably going to be the case most of the time. Now if you add a Draenei's Heroic Presence to one of those then it drops again to 210. So all that said, I still say that a good number to go for to be safe is 315 for hit.
I will probably still be aiming at more like 237, taking a chance on always having either improved fairy fire or misery as I will still be trying to max out my crit.
FULL TABLE
Base chance to miss on a raid boss while dual wielding is 28% with auto-attack on both hands.
Your base chance to miss a special attack is thought to be 8%.
With 5/5 Precision:
Special 99
Poison 315
White Dmg 755
With 5/5 Precision and Improved Fairy Fire or Misery on target:
Special 99
Poison 237
White Dmg 755
With 5/5 Precision, Improved Fairy Fire or Misery on target, and Heroic Presence (Draenei):
Special 66
Poison 210
White Dmg 722
Expertise Rating Cap:
Your base chance to be dodged by a raid boss with any attack is thought to be between 6.25% and 6.5%.
To cover 6.5% chance:
0/2 Weapon Expertise: 214 (26 Expertise)
2/2 Weapon Expertise: 132 (16 Expertise)
Human wielding swords or maces with 2/2 Weapon Expertise: 107 (13 Expertise)
In other words you want the number beside your Expertise on your character screen to be 26/26 to max it out. The numbers above are just what you need to get there.
Crit Cap:
The crit cap changes depending on how much hit and expertise you have. The more you have, the higher your crit cap is.
Max Crit attacking from front : 100 - (6.5%D + 10%P + 28%M + 6.5%B + 25%GB) = 24% + expertise%(negating dodge) + expertise%(negating parry) + hit%
Max Crit attacking from back (target cannot block or parry) : 40.5% + expertise% + hit%
Expertise lowers your chance to be dodged or parried so the maximum it can affect the max crit is the chance that you will be parried since it has the highest percentage. However, as you can see in the attacking from the front formula, you still have to take off a % for dodge and a % for parry since it reduces both.
D = chance to be dodged
P = chance to be parried
M = chance to miss
B = chance to be blocked
GB = chance to land a glancing blow
The absolute crit cap is 75% which you would only be able to take advantage of if you maxed out your expertise and hit.
Armor Pen Cap:
100% armor penetration - 1400 armor pen rating
85% armor penetration (Mace spec) - 1190 armor pen rating
The armor pen cap is not affected by target debuffs (ie. sunder/faerie fire).
Common Talent Tree Specs:
Combat Spec
Rupture Cycle(5pts are in cqc for weapons in this example but should be put in whatever weapons you are using)
Ruptureless Cycle(5pts are in sword specialization in this example but should be put in whatever weapons you are using)
Mutilate Spec
Rupture Cycle
Ruptureless Cycle
Combo Point Rotation:
Combat Spec
There is not currently a set combo point rotation but this is what I like for a rupture cycle:
5s/5r/5e
The main idea is to keep slice and rupture up as much as possible while using "filler" eviscerates. After the first 5e, to determine what to do next you should check 2 things:
1) Is there at least 10sec left on slice? If not do a5s next.
2) Is rupture still up? If not do a 5r otherwise keep doing 5e's until one of those conditions fails with slice getting priority over rupture.
So you might have cycles that look like 5s/5r/5e/5e/5s...etc.
There is a ruptureless cycle too. All you do is replace the 5r with a 5e in the rotation above. It is not advisable to go to this cycle however until you get, in my opinion, at least 3 pieces of armor pen gear (gemmed for it too).
The only difference in what I say and what the forums say here is that you can start slice and dice with however many combo points you want.
Mutilate Spec:
There is not a set combo point rotation. The main idea here is to keep rupture, hunger for blood, and slice and dice up as much as possible while using vanish as much as possible for the overkill buff. So all that said, here the things to check:
1) Is there is a bleed on the target (from anyone)? If so, use hunger for blood otherwise 5r.
2) Start slice and dice however you want. I would suggest 5s.
3) Is hunger for blood about to run out? If so, refresh it otherwise do a 4 or 5 point envenom.
4) Keep doing 4 or 5 point envenoms until either your rupture is about to run out of you need to refresh hunger for blood all while vanishing when you can to get the overkill buff.
So you might have cycles that look like 5r/hunger for blood/ 4e or 5e/4e or 5e/4e or 5e/5r/hunger for blood...etc
The thing that changes if you do a ruptureless cycle is that you don't do a rupture unless you need it for hunger for blood. You rely more on other players having a bleed on the target.
Poisons:
Combat Spec
Rupture Cycle:
Mainhand-->Instant Poison
Offhand-->Deadly Poison
The reason Instant is now used instead of wound is because they changed the way deadly works so it applies your other poison when it has maxed out which pushed instant back up there not to mention the change in talent specs.
Ruptureless Cycle:
Mainhand-->Instant Poison
Offhand-->Deadly Poison
Mutilate Spec
Rupture Cycle:
Mainhand-->Instant Poison
Offhand-->Deadly Poison
Ruptureless Cycle:
Mainhand-->Instant Poison
Offhand-->Deadly Poison
Weapon Info:
Combat Spec
Speed - You generally want a slow weapon in the mainhandand a fast weapon in the offhand. Slower weapons tend to have a higher dmg range which is good since sinister strikes are done with the mainhand and depend on weapon damage. Also procs from the offhand such as sword spec procs are given to the mainhand. So if the offhand proc'd an extra attack, the mainhand would be the one doing that extra attack. The reason for faster weapons in the offhand is that you hit with it more often which gives you more chances to gain energy from the combat potency talent. Also by the same token, if you are sword spec, you get more chances for that to proc.
Damage vs Dps (assuming weapons being compared are the same speed) - Damage is more important.
Mutialte Spec
Speed - Generally you use a slow mainhand and fast offhand. However speed is less important than dps. You want high dps weapons regardless of speed.
Damage vs Dps (assuming weapons being compared are the same speed) - Dps is more important.
Glyphs:
The current best ones to use according to the forums are:
Combat Spec
Major (Rupture Cycle): Glyph of Sinister Strike, Glyph of Killing Spree, Glyph of Rupture
Major (Ruptureless Cycle): Glyph of Sinister Strike, Glyph of Killing Spree, Glyph of Eviscerate
Mutialte Spec
Major (Both Rupture Cycle and Ruptureless Cycle): Glyph of Hunger for Blood, Glyph of Mutilate, Glyph of Rupture
None of the minor glyphs really do anything to help your dps no matter what your spec last time I looked. About the only one I really like to have is the Glyph of Blurred Speed (there is nothing like being able to run on the water:P ).
I copied this from my guild forums although I did write this guide.