I had problems with my battery life and looked a bit deeper. Turned out that pulseaudio, the process that handles audio routing (and more) used up lots of cpu. It seems I triggered it using a stereo headset the switches to duplex low audio (no idea about the right term atm) when a call arrives. After restarting the unit it went away but only with the recent pr1.1 firmware update the problem seems to be permanently fixed.
So maybe your unit experiences the same problem, you can check by installing the load applet from the extras repository (i think it's already in there). It will display the cpu usage and the memory consumption in the 'taskbar' on the main screens as small bars. If the left bar (indicating the cpu usage) is not very small and grey when the device is idle, then you might have some background processes eating up to much cpu time.
If you want to dig deeper, in the extras-tools repository is an console application called "htop" that lists all running processes and lets you list by cpu or mem consumption. It's a console tool though and has no nice UI, also I don't know out of my head if it needs root access or can be started as user (i think the latest version comes with an icon to start it with, that should indicate it can be run as user, but as said - I'm not entirely sure).
Important is also to watch the device behaviour in idle mode over some time, in my case pulseaudio only 'acted up' for periods of time and not constantly.