I have a problem with Pidgin 2.5.2 in Linux (Ubuntu 8.10). When someone sends me a message no sound is played (the tray indicates a new message and blinks, that's it).
Sounds play fine when I send someone a message. If I preview the Message received and Message sent sound events both of them do make a sound. Automatic and ALSA is what's working from the alternatives in Sound method selection.
I include a screenshot containing a lot of relevant information: