Unless Blizzard makes all those BOP items that an Armorsmith makes into BOE, I would go with Weaponsmith. The only item you will be able to make as a AS is the Breastplate of the Kings line. Everything else barely sells and no profit or it's BOP.
Well it really does depend on what your looking into doing. I chose weaponsmith so i can make Deepthunder, its a pure damage weapon that i've seen work pretty good in arena. But if i chose to raid, i'd go armorsmith for more pve dps items.
just get u skill to 375 make it weaponsmith if u are warr then better swordsmith and wen u get at 70 and u have done u sword and u have skill 375 then u can change u weaponsmith in to armorsmith so u have the 2 of them i 67 warr weaponsmith swordsmith and i only have 344 skill but i buy plans of armor so i can make armor to lol .........hard to do skill :(
i agree with the above comments about armorsmith, most of the items are BoP but if your an MS warr like myself the brestplate of kings line becomes very nice to use (even easier now that primal nethers are sellable). Ive seen hunter weaponsmiths and pally armorsmiths as well.