mp3Gain - Normalizes the volume of mp3 files so they are all the same volume. mp3Gain prevents those "Ouch! That's loud!" moments. (XP/Vista 32/64bit)
SharePod - Allows sharing music between iPods without installing software on a computer. (XP/Vista)
vmcNetFlix - A great add-in for Windows Vista Media Center that integrates the NetFlix WatchNow service into Media Center. (Vista 32/64bit)