It is said that 320kps MP3 is truly indistinguishable from the original. It is also said that for most people 192kps is also indistinguishable from the original, but 128kps is pushing it and at 112kps artifacts get noticeable for a distinct proportion of music and listeners, but it depends on what you're listening to the result on. Cheap in-ear headphones? A lot of people get away with 96kps or even (shudder) 64kps.
Ogg Vorbis at 64kps is roughly the same as MP3 at 128kps, but the artifacts are different and, to a lot of people, nicer. ATRAC3plus (Sony's codec that began life on MiniDisc) at 64kps is about the same as MP3 at 256kps. I tried MP3 some years ago and decided I liked the idea of Ogg Vorbis better. But it tied the music to the computer, and that didn't work with how I listen to music, so my music collection only grew slowly. I've since made my choice of MiniDisc (specifically Hi-MD) and gone ATRAC3plus.
Wade.