I have been having the same problem with audio skips / dropouts since I installed Leopard recently. (I have an iMac PowerPC G4 (3.3) )It didn't start immediately (first some of the videos in Safari but not in Firefox), but it's affecting all audio (even iTunes) pretty much all of the time now. It's extremely annoying, and difficult to explain to me 5-yr-old why the computer isn't working. Since I just bought Leopard, I have the 5.5 version. If I take the disks in to the Apple store, do you think they would be willing to give me a 10.5 or 10.5.1 version?? I'll have to figure out how to downgrade soon...