Depends on the server, and what you are willing to do with the raw mats. Personally I mill/prospect. On my server that does better than raw mats. For a while Ghost Iron was going like crazy because everyone wanted the new Mount. Now that the rush is over, it's leveled out more and prospecting is worth more for all the new gems everyone needs for the new gear.
Personally I've been leveling RaF teams to get ready for the next X-Pac with the Garrisons. The limited information we have currently suggests that we will be able to spend gold for the upgrades we want in the garrisons, so I'm stockpiling gold and mats.
The short answer is, you can bot just about anything you want in WoW still.
I'm sure others will give some input also. There are many ways to earn gold and there really isn't one single "best" way that applies in every situation. It also really depends on your needs in regard to how much gold you need or want to make given a certain amount of time/energy invested.
If you are comfortable with the AH prices, then go that route.