I work in an ER. I definitely recommend having some sort of ID like the RoadID. (I wear a Medic Alert tag because of a serious medical problem.) I would go for the wrist or ankle bracelet over the shoe tag. If you're in an accident where you can't talk to the paramedics, your clothes are probably going to be cut off and the ID might be lost. I'm not a fan of dog tags, but I've come around to liking them more. I would never put it on your helmet. That's going to be taken off right away.

I would put name, contact number, any medical problems, allergies and medications. I wouldn't worry about blood type. If you need blood you'll be crossmatched. In a severe emergency you'll get O- while they're awaiting the crossmatch.