The Etymotic and Sure buds in the $100 range are considered very good. If you're really neurotic and have lots of money to spend, you can pay a lot more for the pricier models, but I've had the Ety ER-6's for a couple of years and think they sound just great. One thing to consider when considering these 'buds is that to get a good seal, which means good isolation from outside noise, you have to take the time to insert them tightly into your ears. Some people don't like the feeling, but the sound quality, especially the bass, is worth it. Those $20 models that are popular with the MP3 crowd aren't in the same league.
