When doing any more than 30 min of riding, I use Earmold plugs to reduce the noise and to listen to my iPod. Near misses occur without using earplugs as well, L plater nearly took me out at 100km/h yesterday, no ear plugs then (mind you, no indicator or horn was used, they were cutting back into my lane).
Using ear plugs helps reduce the stress of loud helmet noise at high speed (I do big km's weekly). Even if you didn't wear plugs, the wind noise blocks out noises so you are less likely to hear squat.
With the molded ear plugs, I can play the music at a very low level and can hear traffic noise, it basically only blocks the wind noise which is good.
Personally, I think cages driving around in the sound proof cars with even the stereo turned down low, has less knowledge of what is going on around them than a scooterist/motorcyclist has with the molded earplug and speaker setup.
Each to their own really, but after doing 1400km in a day on a motorcycle and your ears are ringing for week afterwards, I know which option I will take every time. You only get one set of ears.
"Being cold is the result of laziness" - Bunta Fujiwara
Current ride: Yamaha XT660Z Tenere.
Gone: Piaggio MP3 400ie, too unreliable in the rain (think Italian electrics).ScooterZine