If you are looking for a good set of earphones to help improve your listening experience on your MP3 player, Razer has a fantastic pair called the Pro|Tone m100 In-ear Ear Phones.

The m100’s are comfortable for extended wear, physically block external sounds and have an adapter to allow them to be used on most commercial airline flights. To keep the extra ear plugs and other items together, Razer includes a custom carry case as well.
Review excerpt: "The three different sizes of ear plugs that Razer provides allows for a good fit for a wide range of users, even if your ears are reminiscent of Ross Perot. The ear plugs both seal the good sounds in and the bad sounds out by physical blocking external noise." Read the full review here.