I use a 40G iPod and Shure EC3 earbuds. All I can hear is the music. I can still feel the bike, but I rock and roll down the road. The Shure buds are excellent, but were pretty pricey, about $150. I use them for longer trips, not usually around town though. I have over 15,000 songs and the iPod is only 65% full. Good variety of tunes. I setup a "Roadtunes" playlist before I hit the road and they just shuffle away as I ride.
