Here is a list of free tools that can be useful almost to anyone (they are not over-specialized):

Mp3tag – Auto Tagger and Renamer

XRecode Audio Converter (several formats supported, including ape, wav, flac and mp3. A reliable converter that works also with multi-core processors for great speed)

Audacity Audio Editor (to cut, paste, combine, mix, trim, apply effects)

CD Art Display to Desktop (to enjoy viewing the covers of your disks on a corner of your desktop, or even full screen, while you listen to them)

Exact Audio Copy CD Ripper (to get rid of your space-consuming cd collection and transfer it inside your PC, copy friends’ disks, etc)

Kernel Streaming Hi End Plugin for Winamp — get the Wasapi if you use Foobar; both offer bit to bit exact sound quality. You don’t need any of them if you use AIMP.

Playlist Files Copy – Move from several folders to a single location (when you need to burn a jukebox disk, perform batch editing, etc)

Mp3Utils will let you split your playlist (if it is too long, and you need to burn it to several disks)

Playlist Fix (if you moved files, changed drive letter, etc., and your playlists have broken)

* Check also Audio freeware for a really powerful, PC based, Hi End system