i bought the bike speakers from walmart they work nice and are realy loud i had to come up with and alternative mount though because my handlebars arent flat and straight but otherwise they work out just fine you can hear everything the only bad thing is that it only comes in white so i spraypainted mine black and it was only 15 bucks and holds your portable device with these little elastic straps it has i would recomend it
I got a little cheapo flash MP3 player recently, partly to have music while riding. I tried a little "bag speaker" that your music player goes inside, but mounting it to the bike was a hassle and overall it really didn't work that well. I rode a couple miles messing with it, then turned around and went back home, and got the headphones instead.
What I found was what a lot of other people said--that quite frankly, headphones work best. You can turn them down to where you can hear ambient noise, so it's not much more a safety risk than having speakers on the handlebars would be. And the earbud kinds are placed in your ears, they don't take a lot of power to run--so the music player's batteries last quite a while too.
In a lot of places, operating a vehicle on the road while wearing headphones is illegal...but from a safety standpoint it's no worse than someone driving around blasting music from a 1000-watt car stereo, and people do that all the time, and there's no penalty for it. Saying headphones are bad when people are allowed to blast music at deafening levels from regular speakers doesn't really make too much sense.
I got an "Ultra" player from TigerDirect, it was $50 after rebate.
It's 2Gb flash RAM and also has an FM radio. .....You may see these ipods that have 20Gb or whatever and think 2Gb "isn't very much"----but 2Gb can hold about 350 songs ripped at 192Kb/sec. If you had songs ripped at 128Kb/sec (a somewhat lower sound quality) you'd be able to get around 500 songs on there.