I'm starting out with a total of about 65k gold across my various characters (Kirin Tor, Alliance).
I've got three plans I'm pursuing:
Gathering. I've already made about 3k gold just off of the herbs and ores I've gathered with Aeven in the first half of the Jade Forest. The price per unit isn't sky high, but it's high enough that I expect farming ore and herbs for a while to be a decent money maker. I've also got a good stockpile of Outland and Northrend ores and herbs that I'll be selling to folks leveling their Pandaren characters.
Materials. Stuff that comes from killing mobs - primarily, cooking materials, enchanting mats and windwool cloth. For now, if it's a cooking reagent, cloth, or something else usable by a profession, it's going on the auction house for the best price I can get.
Bags. I've got enough materials for about 400 netherweave bags and 40 embersilk bags socked away on Laenshield. While this won't make nearly as much money as gathering or selling materials, I expect it will generate a few thousand gold.
Once the prices for ores, herbs and other materials starts to trail off, I'll start stockpiling materials to level my own professions. I'm not a raider, except very casually, so having the absolute best gear really isn't an immediate priority for me. I'm hoping to get to 200k gold by the end of October - enough to fuel whatever initial pursuits might be interesting in MoP.