Smiths are good at pvp (for crafters) and an integral part of towns. My town would be in a bad place without our resident smith. I have been raped by a single smith spamming repair macros when I was a cleric, and I had a dragoon and another guy with me. Also, speaking as a master engineer, engineers are fun, although you are required to keep your systems relatively uncomplex to prevent lag on the server. (uncomplex means nothing with tons of clocks and crazy shit, you can make awesome piston doors and elevators and traps).
So in summation: smith for pvp (esp. with repair macros, they are excellent at it), engineer for systems and traps (more of a "thinking man/woman" spec)