
Yeah, they're in-ear earphones. When I first picked them up I was pretty impressed with their sound quality, a definite step up from the earbuds I was using before. After a while though I got used to them, and then they seemed rather ordinary. And then I switched back.
Whoah. After accidentally leaving my main mp3 player and CX300 phones at a location other than home, I was forced to switch back to my old Philips earphones. They didn't suck by any means but... they sucked. I listen to mostly rock music which does have a noticeable amount of instrumental detail with the right earbuds, but all that detail I had discovered with the CX300s was totally lost when I used the Philips.
And therein lies my final motivation to actually write what I have believed all along - folks, if you're going to get an mp3 player, please, please invest in a set of decent earphones! I fail to see the logic in spending hundreds of dollars on an mp3 player yet refusing to spend less than half of that to get earphones that actually do the mp3 player and your music justice.

Especially iPods. (No bias, seriously!)
But really, all mp3 players are privy to this. If you don't believe me, look at the ever-shrinking list of accessories that come with mp3 players - they used to give us AC chargers! Nowadays I can confidently state that pretty much any mp3 player that you can purchase comes with the following components:
- MP3 Player
- Earphones
- USB Cable
Trust me, if they can save a few dollars on those last three components, they will.
Anyway, back to earphones. The foremost reason why there was such a massive difference in instrumental detail between the in-ear earphones and the standard ear buds came down largely to the different designs: while ear buds sit outside of the ear canal, in-ear earphones do as they say and are designed to be inserted into the ear canal. Not too deeply, mind you, but you do have to get used to it.
The additional sound isolation also means that you don't have to play your music as loud as you would have to with standard ear buds, since that music no longer has to compete with outside noises, so you're less likely to hit the ceiling limits of your mp3 player and subsequently experience ugly and very-bad-for-your-hearing channel distortion - especially for the treble channels.

In short, in-ear earphones enhance your music while being better for your hearing. So why use earbuds at all?
Well, it still comes down to personal preference. I wouldn't be surprised if many people were turned off by the concept of jamming anything into their ears, let alone something which pumps sound directly into them. Also since in-ears are coupled directly to your ear canal, you will hear every noise transmitted down that wire... and not just electronically. If the wires rub along your clothing then you will hear a distinct and annoying rustling noise, which makes in-ears probably not so ideal for joggers or people who almost-miss trains often.
You will eventually get used to in-ears though, and the rustling only happens if you move around a lot. And I'm sure that we aren't all joggers.
So please, if your music doesn't compose entirely of music whose main instruments are the 'umph' and 'tish' of a synthesizer (which, unfortunately these days, isn't exactly unlikely), invest in a decent pair of earphones, specifically in-ear earphones. You'll like your music more, and you'll still be able to hear it to in twenty years time! I paid $70 for my CX300s, and after hearing how they compare I'd be more than willing to pay more for a good set of earphones.

If you don't want to spend too much, then at the very least go for the Creative EP-630s, because even at $40 I know they sound much better than bundled ear buds.

They even come in white. Especially handy for those of us who enjoy the thrill and excitement of a mugging.

