Farming isn't typically my game, but I want to get my main character to 85, so I may as well do it with some economic efficiency. I regret that I didn't pick up herbalism to go with mining because in about 5 hours of play time today, I made 22 bubbles of experience simply by mining Obsidium Ore in Mt. Hyjal and then Elementium and Pyrite Ore in Uldum.
There is an absolutely fantastic route in Uldum along the Northern and Western walls of the zone where you just rake in the experience and ore at an incredible rate. I had the area to myself for a few hours this afternoon and I ended up with a huge number of stacks of Elementium, plus about five stacks of Pyrite(this expansion's equivalent to Titanium Ore). Additionally, I had over 100 Volatile Water/Fire/Earth to go along with a smattering of uncut gems, several of them rare. I'd say if you can get this spot to yourself within the next day or so, don't leave. It will never again be this good.
Obsidium seems to be selling at a higher price right now on the AH, but I would expect Elementium to hold steadier when enough players get to higher levels and begin to produce the items players truly want. I also realize that this magic spot won't be there forever, and if you put two or three players flying the same route, it will go from fantastic to pathetic very quickly. The plan is to move to Deepholm when I make it to level 82. Supposedly it has a lot of great mining too.
As for the Auction House, twink-blue items are selling like hotcakes. I'd stocked up on about 100 of them, and they are selling for triple or more what they were just a few days ago. Expansion fever has hit, and I've probably made well over 10,000 gold since this morning on just the twink gear plus a bit of my mining efforts.