I think this one looks best in black and white, 100mm (macro), f/8.0, 0.4s, ISO 400.
These are the best of the bunch of photos I took. I like that I can actually see the crystalline form of the flakes. If I had had a little more time before they melted, and hadn't been shivering, I might have got better shots. The flakes were gone within seconds of falling.
I pumped up the blue tint a little for this one, 100mm (macro), f/8.0, 1/10s, ISO 400.