I have a feeling a problem I have may be related to communication with the 27" Apple display and a Nehalem Mac Pro.
Any use of any audio will repeatedly cause hangs in AE (CS5 all latest updates).
This is temporarily fixed by turning the audio hardware preferences off and on again, which takes a second or two to register.
I also have headphones plugged into the tower which I take out from time to time so clients and supervisers can hear as well.
I know this used to freak after effects out a little as well.
But now it has got very bad and I really think it is something to do with "system default" flags between display and system or display and after effects.
I have noticed other people posting similar things but not thinking about the dis[play audio.