HI,
So...
Like mine it reads Headphones but is in fact a device that is plugged in to that Socket.
You can see that I have some Extra (Custom) sounds and these are stored in ~/Library/Sounds.
Do you have any additional Sounds ?
If yours are Built-in (System) ones only which ones are listed ?
The System ones are the ones you were talking about at the beginning.
In Messages > Preferences > Alerts are the ones for Messages (They are tucked away in the App).
Do the Sounds Play in Messages when you test/change them ?
Select the current choice showing in the sound choice drop down to Play in Messages.
This volume may be different to the System Alerts as they are played by different methods.
Does Skype have similar sounds for Logging in, Inviting and connecting and so forth ?
Can you hear those ? (either in the App or as Alert sounds in normal use)
7:49 PM Saturday; November 3, 2012
Please, if posting Logs, do not post any Log info after the line "Binary Images for iChat"
iMac 2.5Ghz 5i 2011 (Mountain Lion 10.8.2)
G4/1GhzDual MDD (Leopard 10.5.8)
MacBookPro 2Gb (Snow Leopard 10.6.8)
Mac OS X (10.6.8),
Couple of iPhones and an iPad
"Limit the Logs to the Bits above Binary Images." No, Seriously