I have finally just got around to updating my N900 to the most recent thumb update and am noticing that the CPU is now consistently between 40%-60% usage.
Using the "top" program from a terminal shell I see that
/usr/bin/hildon-sta and
usr/bin/pulseaudio are the two programs using the CPU.

I have tried rebooting the phone, even removing the battery, but the same thing is happening - CPU constant between 40-60%. I was running the previous thumb update for the last couple of months and this CPU issue did not occur. Any ideas please?