I would like to get some answers to this important question too. I'm new to road cycling (about 4 months) so I'm by no means an expert. I use a $30. mp3 player from walmart, and it works just fine for me. As far as safty goes, when I first saw cyclists on the road, I thought they were nuts! It looked more dangerous then riding motorcycles, and I ride motorcycles. At first I tried to use one of those helmet mirrors, which didn't work at all, so I gave up on that. After riding a few weeks and getting used to cars and sometimes trucks passing me (sometimes pretty close

) I came to the conclusion that by the time I realize that I'm going to get hit, I'll probably already be on the ground on the side of the road somewhere. So I decided to put my mp3 player on, enjoy the ride, and hope for the best. Its not like I cant hear anything, but I do admit it reduces safety. I would love to hear more on this subject.