If you need some help deciding which wire you need to begin your jewelry and beading projects, use this list of wires (complete with gauges and hardness) as a good start:
Gold-filled 22-, 21-, and 20-gauge round dead-soft wire
Sterling silver 22-, 21-, and 20-gauge round dead-soft wire
Gold-filled 24-, 20-, and 16-gauge half-hard wire
Sterling silver 24-, 20-, and 16-gauge half-hard wire