In westfall there are Dust stormers wandering around (a tad bit rare but easy to find if you have an epic mount :P) and these elementals drop a certain item called [Magic Dust] http://thottbot.com/?i=4512 which are very usfull for one of the bosses (Simone the Seductress and her pet demon) in the epic hunter quest that all hunters have to do to get their epic staff and bow. Not only is this a great item to have if you fighting the demon, but it sells for quite a bit on the AH. I even made a good profit off of farming these for a little bit (Usually I sell them for about 3.50g per Magic Dust)
The great thing about the item, is that even a level 15+ can farm Magic Dust and make a good profit.
Note: Really helps to be a hunter (due to track elementals) with an epic mount (Since the elementals are scattered throughout Westfall)