Let us establish some solid facts as a basis for this matter. The SPL limit for human hearing is approximately a little less than 10 dB of volume in the most sensitive frequency ranges(the same ones used for speech). The frequency limit of human hearing is approximately 20 to 20 000 Hz. If you(yes, you) are using a regular $150 CD player, you probably have nothing better than a 20-bit DA converter connected to regular $300 speakers and an average 0,5% THD stereo amplifier built with ICs instead of discrete components. Its signal-to-noise ratio might be 70 dB or so. Of course a lot of people out there are audiophiles extraordinaire, but since they are already pissed about every part of the abovementioned stereo, they have bigger fish to fry than mp3.

Some people state that "when mp3's are encoded, specific frequencies are removed and discarded, frequencies that are said to be unheard by human ears." This is not true. If you look up a textbook on human hearing, you will notice that the sensitivity of your ears is not uniform throughout the frequency range 20Hz-20Khz. Instead, you have a lot better hearing in the middle of that spectrum. Mp3 uses this(and a lot of other physical facts, not just psychoacoustics) in order to compress music as carefully as possible. Few people complain about the bass in mp3s. Some people complain about the treble in mp3s. A lot of people complain about the midrange in mp3, especially about the elusive "warmth" of the sound. Snake oil aside, it is a scientific fact that this is the frequency range where human hearing is the most sensitive. It is also where the mp3 algorithm does the least of its compression. In fact, the test song used during the development of the mp3 algorithm was Tom's Diner by Susanne Vega.
why? Because Karlheinz Brandenburg, lead of the mp3 development project at the Fraunhofer Institute for Integrated Circuits, used it during testing specifically out of a need for "warm" vocals.

Some people refer to failures of mp3 compared to CDs. The mp3 algorithm has the unfortunate disadvantage of being based upon the abilities of the compact disk. Tomlinson Holman, who developed the THX standard and coined the term "5.1 channel", has suggested an ultimate goal of 10.2 sound, with an array of seven speakers covering the front of the room, plus three speakers in the rear area and two subwoofers, one on each side at 180 degrees.
Does it still sound like mp3 is the issue you have to worry about? Isn't it possible that a 256 kbit, 96 kHz, 10.2 channel mp3 ripped from DVD-audio might be a whole lot better in every way than CD?

Courtney Love has publicly stated that she thinks mp3s sound like shit. She did this in a speech where she also spoke at length about how bad the availability of alternative music on Napster is. Isn't it possible that the fact that most of the music on Napster is encoded by everyone and their dog at 128 kbit or les, downsampled to 22 kHz or ripped from scratched records might have something to do with it? Can you honestly tell the difference between a 192 kbit mp3 ripped by a dedicated mp3 piracy group and distributed with an .SFV file to verify data integrity and ripped from a new, unplayed and clean original CD? Can you do it even on the aforementioned $600 stereo?