With Kael's death just a gnome's throw away, we'll be climbing up Mt. Hyjal soon. However, Baracko has recently brought to our attention that most people still lack their Medallion of Karabor.
Just by looking at the stats, you can tell this will be useful for something other than a (now) defunct instance key. It is a mandatory item for a few situations: namely Anetheron and Mother Shahraz.
Thankfully, there's a list of Shadow Resist Gear at this link:
http://www.wowwiki.com/Mother_Shahraz/Shadow_resist_gear
And now the Q&A before the QQ:
Q: Shadow Resist is da poop! My greens will save me!
A: The greens are a good way to get started, yes. But even if you manage to grab every +stamina/SR item on AH, your DPS & HP pools will still pale compared to the massive stat leap the items in the above list provide. Yea, you'll seem uber in the face of warlocks & these mobs, but what good does it do you if you got the punching power of a 12-year old?
If need be, collect greens to act as "filler" items (belt, bracers, pants, etc.) before crafting the epic stuff.
Q: Where do the Hearts of Darkness come from? How can I get some for crafting my stuff?
A: Hyjal/BT trash, or performing special "favors" for people already farming these instances. As for availability for when our own raid starts seeing them? Ask the officers when that time comes. Keep in mind they are used to craft other crazy-strong items besides the Shadow Resist gear, so DON'T BE STINGY!
Q: Hmmm....a lot of that crap requires Ashtongue Deathsworn rep.
A: If you did your homework and completed your chain to get the Medallion of Karabor, you should be well into 1900+ points Neutral with these guys. Some of the patterns become available from Friendly and up, which can be acquired via killing BT trash.
The vendor is a Broken named Okuno.
Q: I can't find the Greater Shadow Resist to Cloak formula! /wristcut
A: Grab your enchanter buddy, and go farm Voidshriekers. You may get this on the first kill, or after your first one hundred kills. Results may vary ^_^
Q: My SR is still kinda wonky. Got any ideas for my miscellaneous slots?
A: Yup. This link has Gear Guides for the other slots and consumables. Keep in mind a good portion of this stuff comes from quests, mindless crafting/farming, or pre-BC instances (Naxx).
Some items from BC still don't show up on that list, like green L65+ rings/necks. Don't be afraid to go the extra mile just to number-crunch!
EDIT: Added colors for a bit more "whoa".