What do you need to consider with armature wire? You need it to be strong enough to hold up the figure, bendy enough to be easy to work with, and it must not rust You never know, but your doll may get wet at some point, or be subject to humidity.
Gauge is also important. Size 18 seems to be the most popular. 20 or 22 is thinner and okay for arms. Chenille stems are good for hands and can be used for small dolls. They can even be braided together for strength on a small figure. the electrical wire I use comes covered. When you strip the cover, you get two coated wires and a copper ground wire. I find this works very well and I'm recycling old wire, which makes me feel good!
Now here's the new thing I learned: bonsai wire comes in copper and aluminum. It comes in different gauges and is cheap! If you buy wire at the art store or hardware store, you can pay big bucks for it. This stuff can be found at some hardware stores and online - cheap! I like that! So that's my next purchase, once I use up the electrical wire that I have.
What kind do you use?