Engineering

Engineering used to be just a money sink for pvpers pre bc and most of the early parts of bc. But in the recent patches blizzard added the zapmote extractor and added lots of mote spawns.

Farming these will get you Motes of: Air,Water,Shadow,Mana. In Nagrand,Zangarmarsh,SMV,Netherstorm.

Also if your serious about farming these the epic goggles are a must. Its a worthwhile investment. By wearing the goggles you can see all the clowds on your radar which makes it alot easyer to find them.

Its not quite as good as mining but you get all the other benefits of engineering like the epic goggles and the grenades and little gizmos.

For rogues with engineering you can do the underbog chest farming.