First off, there is no Best.
There is better suited but that depends on what you are trying to achieve.
If you are looking to be able to craft your own armor upgrades, then Leather working might be the way to go, paired with Skinning. (LW's can make Mail at the higher end)
Are you looking for Weapons? Mining Black smithing
Potions? Alchemy and Herbology.
Wanna amass a vast pile of gold? Use Mining and Skinning or Herbology and sell the mats for pure profit.
In short, figure out what you are hoping to be the end result then act accordingly.