I have noticed that the built-in media player of the N900 uses 20-40% (average ~30%) of the CPU (pulseaudio & dbusfw) when playing simple MP3 files. Other media players are worse than that. Is so much power usage really needed or is there a more simple audio player? I can remember my times with an old Siemens S65 which was able to play MP3s while writing a SMS and listening a loong time and it had a very slow processor compared to the N900.