I just dinged 80 last night...and almost am capped with my defense. But I soon realized to even be considered to tank any heroics...healers want me to have 25,000+ health. I don't see how I could possibly do that without sacrificing too much def rating. Any help?
Get the HoL trinket and you will be fine for def to focus on stam. The JC trinkets are also a great stam boost once you level to that. Wyrmrest has a nice chest that is greatly superior to yours. When I dinged I just decided to dps for a bit then worked up the gear to tank. Only took about 3 days of hardcore heroic running.
I'm hesitant to enchant gear I think will be "quickly" replaced, but also realize that in order to be the best I can at the time being I should really do something on that early gear. Some pieces you think will soon see the vendor can stick with you for a long while. My personal compromise is to get cheaper enchants.
With that in mind, I'd recommend looking into a cheaper stamina to boots and bracers. Even the Argent Crusade shadow resist helm enchant gets you some stamina on a slot you don't have anything, but I can see the 150g price tag might make you, me and others shy away. So instead grind away at that rep with the dailies, they'll also get you cash. As well if you can get the defense cap without gems you can free up some slots for stamina or other gems.
For looking for upgrades I'd say either try to follow some of the guides around here or just searching on wowhead. Here is an example of how I used wowhead to guide my efforts. Just do it for each slot to find "easier" to get upgrades. Plate Armor - Items - World of Warcraft
Make sure you prioritize your heroics to go after the drops you want. As well, don't look past getting upgrades in regular dungeons. HoL has the Loken trinket that's a great way to keep that defense cap and allow more choices in other gear slots.
There is also some very decent boe BS gear, (Tempered Titansteel). As far as enchants go, they really aren't all that expensive. I think with the BS gear and regular instance gear, I was at 25k health with the minimum defense rating when I hit 80. Heroic VH should be your first heroic everyday. Nice pants drop there, ones that I actually like better then my t7 legs. There must be something like this here, but I used this while gearing my dk tank:
I fully agree with DragonMageWTF there are some enchants you can get a lower version much cheaper, look at the +10 to stats vs. +8. HUGE price difference. Also remember how much gold you're saving by always having a free weapon enchant. Although I saw a decent weapon enchant posted from the ptr recently (Enchant Weapon - Blade Ward)
The first thing I'll say is that you can shed a good bit of defense rating for +stam gear. In heroics you only need 535 Def to be uncrittable. You're at 541 right now.
There are some good tanking pieces that you don't have, which drop in the Regular level 80 instances. You should consider going over the drop lists for HoS and HoL, Occulus, etc...see what pieces would be a clear upgrade, and run the instances you need to get those pieces.
Whoever said that the Seal of the Pantheon is good, was dead on. The amount of Def on that one trinket lets you shed def on an entire piece of armor if you want. Certainly worth it.
Finally, work on your rep. You want your Arcanum head slot enchant, you want your Wyrmrest rep items, and with those two things you should be closer to good. A well geared healer can take a 23k health tank through a heroic if the tank can keep threat, but your gear really isn't "heroic" ready. Run more 80 regulars.
Lastly, armory isn't bugged, it simply doesn't display the armor bonus from Frost Presence.
What should my parry/def/dodge/health/armor be at to be able to run heroics without much trouble?
Someone told me it should be 16%/545/16%/25k/20k
But I've heard alot of different things.
Parry: 14% (Assuming Blade Barrier is prioritized and always up)
Def: 535 (seriously. IBF increases with more def, as does avoidance, but assuming the rest of your stats are up to par you only NEED enough def to be uncrittable)
Dodge: 16 or 17% is fine
Health: 24K is good
Armor: I'd shoot for 24k
That's sufficient for entry heroics, like Utgarde Keep and Nexus. You'll want to hold off on Heroic Halls of Lightning and Heroic UP for a while, unless you have a really solid healer and solid DPS.
Also, when pugging heroics, don't carry DPS. If someone isn't putting up AT LEAST 1,400 in a heroic, they're making your job and your healers job harder. You may be ready, and your healer may be geared, but two members throwing down 1,200 DPS will totally obviate your gearing.
At the very least put a leather stamina kit on the unenchanted gear. It's not expensive, and there isn't much of an excuse to not have *anything* at all. Enchanters are often giving away lower level enchants as they skill up, so every a +6 stats to chest is better than the +0 to everything you have now.