Money makin'Follow

It is a very solid combo to make money.
I have herbalism / mining as my professions (yes, two gathering professions on my main char).
I can make tons of gold with mining as ore and gems sell really well at the AH (I make ~100-250g per hour of farming with my epic flying mount).
I really like herbalism as my other profession.
One cannot track both things, but you can see a lot of herbs when flying around and one can still farm for either herbs or ores and still look for the other kind (and you don't have to kill stuff which might take some time as with skinning).
Herbalism generates a lot of gold by selling herbs to the AH and additionally I have all the mats for those stacks of potions/elixirs I go through when I raid (saving me a at least 100g per raid evening).

Problem with mining/herbalism is that you can farm very effective with an epic flying mount. Without that you'll get less herbs and ore, making less money.

depending on how much work you want to put into it, Enchanting can actually make you a lot of money. Of course, to Disenchant the higher level items, you have to put a lot of money into skilling up, but once you hit a certain point, it's pure money from DEing random greens and crappy quest rewards, plus it can benefit you if you manage to get the skill up high enough to enchant your own gear.

But if all you want to do is pay th 30c for a skinning knife and mining pick, skinning/mining is a really good combo.

why? There is nothing which requires a skinning skill of greater than 375.
It is not like pre BC where you had to have 315/300 in skinning to skin onyxia.
Pre BC I had that skinning knife from UBRS and the sword from Zul Gurub (yes I had skinning/leatherworking pre BC and of course I was always broke because of those expensive pots).
I could skin bosses without a +skinning enchant on gloves, but now those things would be totally useless.

I have herb/mining on my farmer, and yes it is very efficient at making money, i have a macro that flips what im tracking back and forth, so thats not an issue. I can see how skinning would be a good profession while leveling, but not once u hit 70, unless you like to spend time killing things. I would rather just fly around and pick things. :)

On my hunter I have skinning/lw. I picked lw to get the bop epic gear, but now that I have moved on, I still keep lw. The reason is that you can make hard knothide leather, which increases the value. My strategy when farming is to find a mob that I can skin and that drops something I can sell. (motes/marks etc)

I find that when I'm mining, I'm flying from node to node, and so it doesn't have very good synergy with skinning. I would suggest herbalism/mining, and just toggling the tracking.