Audio File Manipulation

Free Audio Pack (developed by Koyote Soft) comes with three separate tools:

• A CD Ripper (to mp3, ogg, and wma at fixed and variable bitrates)
  
• An audio file format converter (wma, mp3, ogg, wav, m4a to various file formats)
  
• A direct audio waveform editor (trial only)
  

Download the bundle from ZDNet, or download them separately directly from Koyote Soft.

Another indispensable tool (that you have to pay for) is WavePad which you can download from NCH Swift Sound

In my opinion, while Koyote Soft have done a superb job in offering such useful software for free, WavePad is the far superior program overall - but I think both are definitely worth having.