Like always, keep using the Auctioneer Mod so you can keep up to date with the economy on your server.
As I told you about with Scryers and Firewing Signets, it is a waste of time to put a lot of effort into farming the lowest Aldor item, which is Mark of Kil'jaeden. Around level 65, you will farm wow gold much more efficiently by going after Motes and Primals.
To cover your requirements of Mark of Kil'jaeden for quests and earlier Rep turn-ins, the best farming spot is Terrokar. You go south from Shattrath City to the Bone Wastes. In the north and northwest parts of the Wastes; hunt the Cabal Abjurists, Cabal Tomb Raiders, Cabal Spell Weavers and Cabal Initiates. These are all in the level 62-64 range. You will get lots of Marks of Kil'jaeden, but you will also be getting a bunch of Netherweave and Runecloth. These will both bring you some nice extra gold at the Auction House.
Now lets talk about farming gold big time!
The most efficient spots for farming Marks of Sargeras and Fel Armaments are in Netherstorm... as long as you are level 70 that is. You need to begin in Stormspire and shoot up north to Forge Base Oblivion and Forge Base Gehenna. There are demons here that are in the level 68-69 range and drop Marks of Armament at an extremely great rate. You need to be taking out mobs of Ironspine Forgelords, Cyber-Rage Forgelords and Wrathbringers.
If you are an herbalist and/or enchanter, a better spot is Socrethar's Seat, the island just northwest of the Forge Bases. You can only reach this with a Flying Mount though. The level 70 mobs will give the same rates on drops as the Bases, but you will also get tons of Mana Thistle and Dreaming Glory Herbs here, and the mobs drop green items that disenchant well. Watch out for Socrethar, the elite in the middle of the island; he does not move much, so it is not much too worry about.
If you are efficient in your farming of the Netherland areas, you will bring in 3 Fel Armaments and around 30 Marks of Sargeras per hour. Those stacked with the other loot, all of the herbs and the disenchants too will mean you are bringing in 100g per hour.
Another place to go farm Mark of Sargeras and Fel Armaments is the east side of Blade's Edge Mountains. Towards the south, around the area inside of Death's Door, you will be able to farm level 68-69 demon mobs such as Death's Might, Deathforge Technician and Death's Watch. These will drop Mark of Sargeras at a rate of 25% and Fel Armaments at a rate of 2%.
A little north of here, at Forge Camp Anger, you will find loads of Doomforge Attendants and Doomforge Engineers, level 67-68. These have a bit higher drop rates for the Aldor Rep Items than the Deathforge Mobs, but they are tougher to kill. If you are an engineer, this is the only place you can get the rare Bind of Pickup Schematic for Felsteel Boomstick, which is extremely useful for leveling up your engineering skill past 360. The Schematic only drops from Doomforge Engineers.