Fingers, definitely fingers. I tore a ligament in my right (dominant hand :-( a while back and its absolutely amazing how much you depend on the ole digits to do such intricate work.
Actually, I find my nails grow faster on the fingers I use most for wire work, increased circulation, stimulation, maybe. I don't know. They still look pretty terrible, but cest la vie'.
Then there's the bent-nose pliers, round nose and flush cutters. I'm lost without those three. They go everywhere with me. No kidding. Oh, and a graphite pencil I used eons ago in art class. That's my super-fancy, but oh so trusty, viking knit mandrel. Available anywhere for less than a buck. Necessity is the mother of invention, right :-)