Best software to convert mp3/flac/m4a?

[-AMO-]

I need to convert quite a few audio files to mp3, flac, m4a and vice versa and was just wondering if anyone had some suggestions for one that will be fast etc while giving good results.

Thanks for your help.

[ilscuro]

I use dbpoweramp, it comes with lots of plugins and converts almost all audio files.

http://www.dbpoweramp.com/