Crafting gear is not useless. It speeds up your overall gearing. If you want to get into raiding quickly, you will need to gear up quickly. If not, then it does not really matter which professions you take, they all have one benefit or the other.
For the Rogue or DH, I would definitely suggest Skinning/Leatherworking as you get tons of leather/scales while leveling and then can craft quite a bit of items when your char hits 110 (and you did the profession quests, and - of course - you haven't hung yourself during the "find the 4 skinning racks in Highmountain" quest)
Jewelcrafting definitely needs mining with it and is only for masochists if you want to do it half-decent. Getting those large gems is such a major pain...
Alchemy is always nice, and pairs nicely with the herbalist you already have on the inscription char.