Remember kids... always wear a helmet. (The almighty bikeradar helmet thread)

where's your data for that Ed? or are you just spouting shite you've heard others say?

Wayne old lad, it's basically what Cycle Training usually teach you to be more aware of your surrounding, to look back more often than to rely on your hearing.

listening to music from your iPod is very different to holding a conversation, since you're blocking outside noise, what would you do to compensate for the lack of noise?

I'm not saying that people who wear iPod and the like are always good at riding, the same as people who can hear everything but still ride terribly.