I've gone down 5 times this season, no helmet hits yet (mostly slow motion, here it comes dummy, and i'm on my side or my butt).
I think testimonials regarding helmet use and helmet efficacy are useful. As a matter of fact, I don't think I've heard ENOUGH of them. I'm glad to hear that it saved your commute and, most importantly, saved your health.
I would recommend getting studded tires as they will certainly keep me upright during the long freeze-thaw cycle that we will get here (we have mountains of snow to melt in Madison, Wi.)

a side note to stupidity: this is a university town, and I commute thru campus daily. I see hundreds of scooter riders --even riding on the same black ice as me... and I'd say 1 in 50 wear helmets. Now that would hurt if they went down at their speed.