So, I update to QuickTime 7.1.1, restart and when I come back, after launching Mail.app my CPUs balance at 50% usage (have a MacBook Pro, if I shutdown one core it tops at 100%).
Weird thing is, I check Activity Monitor and there is no single thread/app using that CPU, but it IS reporting that the CPU are being used. Also the temperature rises and the fan revs up (always the final clue that high CPU usage is going on). Seems to only happen with Mail, I don't have any bundles for it, no hacks ... I'm puzled