3/ Did you install EasyDebian (Qole's amazing work) ? ...
4/ Did you install a status bar applet called " advanced power " ? ...
5/ I'm not specialist with home applets (I simply never use it) but i would'nt be surprised if one of them is keeping a connection active to check something on internet ... did you try to put the unit in flight mode ? did you try to deactivate all home applets ? ...
Are you turning the N8x0 off between uses? The boot process consumes a lot of power. It was several weeks before I came to the realization that you should leave your N8x0 on at all times and very seldom reboot.