If you're looking for a great sounding earbud that's midpriced ($50-$60) give the Sony Nude's a try.

http://formen.ign.com/news/33649.html

I use mine with my iPod all the time, and it sounds great. They are great for traveling because they act as earplugs, they are quite portable, and you can even sleep on the side of your head without too much discomfort.