Winamp has long been a popular mp3 player developing a large user community. Members of this community submit a plethora of skins, plug-ins and other add-ons to the Winamp website. Winamp also offers support for iPods and other mp3 players, and functions as an adequate video player.
If you have ever made an audio mix CD from mp3 files, you have probably been annoyed to find that all the tracks play at different volume levels, spoiling that overall ambiance you wished to create with your selection of top tunes. If this problem is a source of vexation for you, try mp3gain. With this program you can quickly balance the levels of a selection of mp3 files, so as to further impress that prospective partner, work colleague, or friend with your eminently good taste.
The best freeware audio editor available is Audacity. It provides support for mp3 files - as well as a number of other formats - and offers enough editing features and effects to meet most user's needs. Unfortunately, Audacity does not support proprietary formats such as wma, but there are plenty of audio file converters available like dBpoweramp.