My Essential Audio Software choices are:

[glow=orange,5,300]OrangeCD[/glow] (This is an obvious choice)

[glow=orange,5,300]MusicMatch Jukebox Plus[/glow] (Some great Super-Tagging features)

[glow=orange,5,300]Winamp [/glow] (Audio Player)

[glow=orange,5,300]Exact Audio Copy [/glow] (Ripping Software)

[glow=orange,5,300]LAME [/glow] (MP3 Encoder)

Enjoy 8)