On top of what MPS_Cowboy has posted in his TBC posts (great, btw), there is one herb, that bears mentioning again.....Fadeleaf.

With arenas coming in TBC, rogues will see more small scale battles and control will be a major issue in there. Hence, blind will be used as much as possible. And you need Blinding powder for that. And you get that from Fadeleaf. And you get Fadeleaf from SM - armoury.

In SM armoury, there is a Fadeleaf-spawn in the first courtyard that yields 1-3 herbs. With 5 resets an hour, that's 5-15 herbs. With two characters doing this, you can get almost two stacks an hour. Or just do Herod runs with one character and sell the silk and drops.

Currently Fadeleaf runs 10-15G/stack, but TBC will easily double this, seeing as how much money people are making leveling up.

So, if you have nothing to do (as most people don't have atm), pick those flowers and profit :)