How does a good mp3 sound?

Has anyone compare the sound of a good MP3 player like creative zen 20gb mp3 player with a cd player?

Is that te best sounding unit now, or is there better?

Is there less jitter than a cd player?

How is the quality compare to a computer with a good soundcard?

There are a ton of lossless formats now, which sound better to me than the original cd. I know the iPod can handle some of these files and I'm sure some of the others can as well.
MP3 ALWAYS is a loss because that's what the Fraunhofer Institut set when the standard was born. No problem in hearing the difference after a couple of bars. Apple lossless according to STEREOPHILE's John Atkinson is a very good encoding format but yet if compared to a CD spinning in a high end transport all these "on the road" formats are great for the road or great for the convenience of, the let's say, the iPod but not really conmparable to what I am used to listen to at home. Excuse me Tutordennis, any encoding format cannot be BETTER than the unencoded original except in Harry Pottter.
Short answer: bad
Medium answer: very,very bad
Given that the encoding process reduces the information content by 90%, mp3's can't help to be horrible. Anybody who can't hear the difference better sell heir HiFi and get a Bose WaveRadio.

If you get an iPod you can use it to play cd-quality
audiofiles. That is if you use a mac and iTunes.
Don't know if that works with Windows.
If you think CDs are perfect sound forever you will love mp3. Both formats are flawed from design to execution, but in a world where convenience is king and quality is relegated to being only for those who are too rich to tell that it isn't any good, mp3 rules the roost.
For a portable mp3 is okay but in a HIFI application all lossy codecs are lacking. Ogg Vorbis (codec) while being lossy seems to me to produce near CD quality if you encode at 256kbps VBR or higher. BTW there is no way in the world any lossy codec can sound as good or better than the source CD....physics 101

If you are considering ripping your CD's and putting them on a PC hard drive for playback via your hifi you should consider a lossless codec like FLAC or APE. These will give CD quality playback and the stored file will be smaller than a WAV file but not as small as a lossy one i.e. mp3, wma or ogg.

Thanks for all the informative postings - sounds like it's time to get back to a Turntable.
Don't give up on digital sound just quite yet. Yes accept that digital sounds different to analog, better worse, like wine its personal.
And yes MP3 has about as much depth as a string tied to a tin can, but given that there are now several lossless compression codecs and given that hard drive space is cheap there is very little reason one would even consider storing digital music files as MP3's.
I listen to a great deal of digital music and having several thousand items cataloged and cross referenced for instant playback has profoundly changed the way i listen to music... better, worse like i said just different...