mining/skinning on mage

in the grand scheme of things does it REALLY make that big of a difference? can i make a ton of money off minin/skinng? or is it such a h uge deal that i should build tailoring/enchanting from scratch?
I personally went Mining and Engineering, and i love it. i can make some gold with Mining, and the toys you get as an Engineer are pretty sweet. Besides, I'm a goblin. We are made to blow stuff up. I thought about being a tailor, also, but since I also have first-aid, i thought that sounded a bit heavy on the cloth.
You might want to take herbalism and skinning instead. Mining makes good profit, but that Toughness buff you get from the profession is not for casters. Herbalism comes with a healing ability.
You sound like you are more looking at the "money making/gathering" approach. To respect that I will say def go for the skinning. It increases your critical strike rating... so that should be a bonus. As for mining... I wouldn't recommend that for a mage. Not over herbalism, as someone mentioned it has a heal, but Lifeblood more importantly increases your haste (Lifeblood got a makeover, so its not just a minor heal anymore). But unless you prefer the extra stamina from Toughness, I would take the gather skill with haste. Its up to you, but skinning and herbalism would be my choice for the money making :)

Also, there is no guarantee that you will make a ton of money going after just gathering professions... But at the same time you may not make any money going after a crafting one. Depends on what you do with it and why you went for it. I usually go for them to get the bonuses, such as enchanted rings, epic gems, shoulder enchants... you get the idea. Selling things on the side just is a pay off to the effort I put forth.

Cheers :)
I'm skinning/enchanting and I have to say that it has been unbelievably easy so far. My enchanting is over 470 (I'm level 84 at the moment) and I've only had to grind a little bit for mats at the end of TBC and Wrath. As for skinning... Well, I maxed skinning at level 75 in the midst of leveling in Scholazar Basin. I didn't even know it was POSSIBLE to max a prof at 525 without touching Cata! But apparently you can do it with skinning. I haven't been making a ton of money but I certainly have been able to sustain myself very well. I bought all my flying training with ease. Having extra pocket money allowed me to occasionally buy what I couldn't DE enough of for enchanting. I'm sure tailoring coupled with enchanting would have been easier to make my own mats but honestly, it hasn't been difficult without tailoring (and tailoring isn't making much on my realm). I queue my dungeons nonstop and DE all the drops I win (and can't wear). Most of the stuff I pick up in dungeons way surpasses stats of my questing rewards so my rewards end up being disenchanted for dust and shards.

Having +80 crit bonus in the level mid 70s made my mage a beast very early on. I've found it to be a very nice passive bonus! And +80 int that I will eventually get from enchanting my own gear will be icing on the cake.
I don't get the min-maxing "best" professions type of thing. Every profession is good if that's how you want to play. I dropped enchanting for engineering because 1: I had money to blow 2: Jeeves, Mailboxes and all that are great for me when I solo stuff and 3: I've always wanted an engineer for the hell of it.

I say double gathering professions is a wise choice if you stick to farming because you can make a lot of gold these days if you put some effort into it.