I've come across three pieces of free software.
Since I probably won't have time to try them out for quite a while, I'll ask if anyone has had good or bad experiences with them...
Supposedly Audacity is the best free MP3 editor; my only use would be trimming the beginnings or ends off song files. Avast! received high marks from Consumer Reports, and might replace my current antivirus software when its annual subscription runs out. Foxit reportedly loads much, much faster than Acrobat or Acrobat Reader.
