I agree, some of these responses are less than helpful. Alas, mine will probably not help either.

I'm a musician and love good-quality speakers. I was amazed when compact headphones came out and offered really good sound in a small, light package. Earbuds are even better for bicycling because they block out some of the wind noise. I've never heard any small, handlebar mount speakers that sound good to me. It's like listening to music on your laptop. My son does it, but to me those speakers sound so tinny that I can't do it, except in a pinch.

The reasons I don't feel that listening to music on earbuds is suicidal are two-fold. One is that I can still hear approaching traffic. I can't hear it quite as easily as without the music, but even without anything in my ears there are always lots of cars/trucks that surprise me when they pass; I didn't hear them coming. So I consider relying on your ears to warn you of approaching trouble as inadequate, earbuds or no. Instead I use a rear-view mirror to keep tabs on traffic from behind. I have mirrors on all my bikes which I ride on roads, and use them. I feel much better able to monitor things with a mirror/earbuds combination than a no mirror/no earbuds combo.

Someone will likely say that a mirror/no earbuds combo would be the best. Probably, but not so much better that I would give up my earbuds. I don't always listen to music when I ride, but when I want to, those earbuds sound great and the music can be a great enhancement to a solo ride.