While I covet my bamboo, I'm a working adult who is underpaid (at the moment, anyway). Bamboo, in my mind, costs a goddamn arm and a leg. I do a lot of "in-the-round" projects, so I'm often forced to use DPNs which I can't find in the sizes I need too often, so I'm forced to get something of a wooden quality.
But if I had my way? Aluminum. They're cheap, easy to find, at any store, chain or LYS, and for god sake, they do not snap in half if you accidentally sit on your knitting bag. Or on them yourself. You don't have to think when one of them looks like a broken twig, "Well. Bye bye $2 and change. It was nice to have you."
And if you have a slipping problem? Knit a little tighter. It'll prevent the snow-slope sliding that the stitches will do (I am convinced they go, "WEE!" off aluminum).