I have recently thought I was going deaf because I was getting new mail and never hearing the sound for it. I thought maybe iTunes was on too loud or something. However, I've just done a test and no, Mail is definitely not playing the new mail sound. Speakers are the internal default ones, volume is up, but when I send mail to myself from a different Gmail account, when it arrives in Apple Mail there's no sound. This happens whether the app is active or in the background. I'm sure I've heard it working a couple of times recently, but it's random and seems to be very much in the minority of occasions. Here's another weird thing it does - when I've received new mail during the day but Mail has been turned off, when I get home and open the application it searches for mail, downloads the new ones, and plays the 'No new mail' sound. I've considered these things might be because I've already received the mail on my Blackberry, but this never used to happen in Tiger, and I'm using a POP Gmail service, not an IMAP one it shouldn't be able to tell I've already had them. I have Dockstar installed but it worked fine with Dockstar before. Might it be causing a conflict somehow? Dockstar doesn't play any sounds, only changes how the mail notifications appear in the dock icon. I don't use iChat so I don't know if this problem has affected other Apple apps. I've read some people having problems with that too. Cheers!