Audion 3 claims to do most everything you'd want to do with MP3 files, including playing, streaming, ripping, encoding, burning, ID3 tag management, support for other formats (including Vorbis and mp3PRO), and iPod management. Features that catch my attention: copy music off of an iPod ("don't steal music"), and record any audio stream (ala Audio Hijack).

Cute Audion pictures. (Well I enjoyed them.)