Quality has always been my prime concern with encoders. I only want to have to encode once, not re-encode when a better sounding encoder comes along. The possibility that I may have to re-encode when Mp4 or some other higher quality format comes along. So I've consequently looked into this as much as possible. And from what I've seen, which includes both "number comparisons" where the sound files are digitally compared by the computer in terms of accuracy, listening tests where several people are exposed to various sound samples in random order of the various encoders AND the original sample, as well as personal opinion etc. the best encoder is generally thought to be the Fraunhoffer MP3 Producer 2.1 or any encoding engine or application that uses the full Fraunhoffer codec. It has the most faithful reproduction after compression. This is both at the standard of 128k/s, as well as at higher bitrates such as 160, 192, etc. though the difference narrows at higher bit rates. So if you're concern is quality, then this is probably the encoder you want to go with. Keep in mind however it is slower than Xing based encoders, as well as several other engines. And you may not actually notice the difference. One thing people tend to overlook as well is that several programs allow you to use third party codecs to encode. Programs such as Audiograbber, Musicmatch Jukebox (I think), etc. allow you to select alternate encoders, as opposed to their internal ones (most of which are based on the Xing codec). Audiocatalyst, the effective sequel to Audiograbber may also allow you to do so, though I am not sure. In any case, it increases the functionality of the Fraunhoffer encoder greatly, as the original encoder only does 1 file at a time, and doesn't have CDDB support. Using the codec through another program allows you to do the rip straight to Mp3 with automatic naming of tracks that you may be used to. I suggest you do your own comparison tests though. Because bottom line, it's your ears that will be hearing it, and whatever sounds best to you is what you should use. Some people prefer other encoders. A relatively complete list of encoders can be found at www.mp3.com . Keep in mind the player also does have an effect on what you hear, as different players use different decoding engines. I am not sure what the best quality player would be. If you'd like to see some info on the encoder and some comparisons, I'll include a few links below. I hope that helped some.

http://www.iis.fhg.de/amm/

http://www.pinoyware.com/fliptech/ac-vs-mp.html

I have allot more links on the subject, however I am at work and don't have my bookmarks. E-mail me if you'd like more.

- JavaJones