i hope there's no new restrictions reguarding music, Headphones or earphones i see as no different to someone having a stereo on in their car to be honest, if anything i'd say music helps me concentrate personally, it helps keep my mind active, my mind tends to wander a lot if its not active which makes me tend to look round at the environment/sky etc... more and divert my eyes from the road.
I've had 2 decent crashes on my bike (both while not listening to music) i say decent crashes, i mean serious-ish kind lol, not too serious though.
Cycle helmet of course makes sense, im one of these who never wears one and am lucky that when I split my head open in 2 places i wasnt too badly hurt. (pulled front brake, went over handle bars, forehead hit the pavement, bike came down on top of the back of my head) cycle helmet would have prevented injury. Still dont wear one, but I know I should and personally feel they should be compulsory, at least when cycling on roads.