For those of you that have the Samsung Epix, there is a new patch from Samsung that will resolve the problem problem with notifications:

The Samsung SGH-i907, known as the EPIX, supports multiple methods of notifications for events through visual and audio alerts. By implementing power saving techniques, a side effect that disables audio alerts was noticed. Samsung has developed a software patch which will now enable the EPIX to provide audible notifications alerts for your emails when the device enters an unattended power saving mode. A previously established PC connection is required to apply the update to the mobile phone using the below instructions.

To get the patch, check out the installation instructions. Thanks for the tip, Jared Miniman.