I have found Safari 3 to be very stable with only the occassional unexpected quit. I got those with the other versions too.

No problem with Acrobat reader that I recall but I note that I am using version 8.1.0

AA does seem to be slower overall just recently, not just inside Safari. I find it quicker to launch Preview and read PDF documents from there.

I guess you have tried the usual first aid for problems like this? Disk Permissions & First Aid.

P