I went straight for annealed titanium. Easy to work with and unless you screw up by firing it too hot shouldn't be a health risk.
Probably talking out my bottom but figure if it's unreactive enough to use for surgical implants then probably better than things that rust or can cause allergic reactions.
I'll chuck my tuppence in with titanium too. I've been using nickel for a while now, but got some titanium 26g and it's so much easier to coil as it won't break when you screw the connections down. Fr easier to get a desirable ohm rating and still be able to fit easily on a deck.