Personally, I'd drop herbalism on your warlock and replace it with something else and take up herbalism in the place of enchanting on your druid.
I'd go with alchemy on your warlock in place of the herbalism. The reason is that you can have one of your alchemists go transmute specialization for the chance to get extra epic gems with your daily transmute and have your other alchemist go elixir mastery for the chance to proc extra flasks. Even if you don't use the flasks, they sell at a marginal profit with no procs but you can multiply that profit quite handily as an elixir master.
The reason I suggest switching herbalism from your warlock to your druid is because druids in flight form can gather herbs without having to switch out. Any other class gathering herbs in Outland and Northrend will typically get on their flying mount, fly around until they see an herb node on their mini-map, land, dismount, gather, re-mount, repeat. With a druid, you just fly down, gather, and fly off. Fast and easy. Extremely efficient. That's what I did. My rogue was herbalism/inscription and my druid was skinning/leatherworking. My shaman is also skinning (I took it for the crit bonus while leveling and it's not horrible for raiding, either). My shaman also kills way faster than my druid, so even though you can also skin in flight form it required an abundance of skinnable corpses left by other people to be worthwhile, which was often not the case.
As a result, I dropped skinning on my druid in place of herbalism, replaced herbalism on my rogue with alchemy, and now I can gather herbs for alchemy and inscription quickly and easily, my rogue is my elixir master and keeps me well supplied with flasks in addition to a daily epic gem transmute, and my hunter (my other alchemy alt) gets me a second daily epic gem transmute with the chance to proc extra gems. It would be a very profitable arrangement if I sold all the stuff I make, but I'm stockpiling epic gems to keep my pally and shaman supplied and the flasks I make are also held for use by my raiding toons.
Doubling up on jewelcrafting is also a decent option. 2 x JC dailies = 2 Dragon's Eyes/day if you were inclined to sell them, or double the tokens to put towards patterns. I have one of my JCs dedicated to acquiring patterns as needed, and the other just accumulates tokens for dragon's eyes that I'll likely start selling off as soon as I get my pally and shaman mostly geared with T10 goodness and my need for them decreases. I've actually got 28 Dragon's Eyes in the bank sitting there so I can re-gem JC only cuts as needed when I upgrade gear.
Blacksmithing is not really a very fun profession to level. It's still probably one of the most material-intensive professions to work through, especially in the 200-300 range, and when you're done the only real benefits are the additional sockets on bracers and gloves (which are nice to have if you're raiding, but otherwise not all that great) and Eternal Belt Buckles. For the time it would take you to mine and/or do dailies to fund leveling blacksmithing, you could buy enough Eternal Belt Buckles to last you to the end of the expansion and probably fund flight training on an alt with gold to spare. I have blacksmithing on my pally because JC/BS is the min/max combination of choice for tanks these days. I also have Blacksmithing on my DK which will probably end up replaced at some point in the future. Either way, the most lucrative professions to have these days are Alchemy, JC, and Enchanting, but Enchanting is one that doesn't really have any benefit to duplicating.
Edited, Nov 5th 2009 12:44am by AureliusSir