Break down the Stats
I'll admit I relied heavily on partial credit when it came to math in school... that being said:
Can someone please outline, simply the target stats for a DK tank:
here is where I am currently with a 'gearscore' of 4085:
health - 28941
armor - 24825
defense - 548
dodge - 26.26% dodge rating of 480
parry - 17.34% parry rating of 385
hit - 257
Originally I used some epic gems to raise my defense; and I'm looking at replacing them, however I just do not know where to go.
Thank you for you time.
The World of Warcraft Armory
Your gear is fine for naxx 10, maly 10, and heroics. I recommend continuing to gather emblems and get all or most of your conquest/valor gear. Then you should be more than ready for Ulduar 10. Also I recommend replacing your offering of sacrifice with essence of gossamer.
Your question is oddly worded, but if you are asking "When can I tank Ulduar 10" a common test is the "Ignis (pre-nerf) check". Go through your gear and make sure you have full Ilvl 200 gear. In addition to the Ilvl 200 gear you should have a smattering of 213 / 219 / 226 gear (3-5 pieces). Tanking 10 man TOC would presumably follow a similar pattern. All 219 gear, and maybe a few pieces above 219.
I'm guessing you intended to post this on the HALP forum. Suggest it be moved by Mods.
There are no "target stats for a DK", provided you hit necessary caps (defense/hit/EXPERTISE), grab everything you can, especially stamina. More avoidance and EH allows you to progress to higher content.
Based on what I see, in addition to instances dhthomps listed, you can do Nax25 and beginning portions of U10 (I'd say up to about Kologarn). You may proceed a bit further, but given your gear that is highly dependant on your skills and raid makeup.
Your best bang for buck in terms of gear upgrades are H ToC (Shoulders) and stam trinket from H AN 2nd boss. From badges, aim for neckpiece and ring.
-Enchant cloak. Even if you plan to replace it, get something cheaper, its better than nothing. Target enchant is probably 16 defense (titanweave)
-Belt can support 30 stam, instead of def/stam. Even without cloak, you can afford the loss on def.
-You seem to be putting alot of str gems in red slots, I'd pick expertise/stam or dodge/stam. Expertise is better than Str until soft cap (26) for threat and even having bit over expertise soft cap it is not a bad thing. Dodge is better than parry through strength, and as DK avoid parry altogether. You can start considering str when your gear is approaching T9 levels.
I would actually not rate the Essence of Gossamer as a high quality trinket for a DK. I have almost always prefered a clickable avoidance trinket to it.
Valor Medal of the First War
Rune of Repulsion
Heart of Iron
I highly suggest a pairing of a Dodge/Parry trinket, or try to get The Black Heart and pair it with your best avoidance trinket.