Ok, good point. Maybe there are a usage cases for both?
Thanks also to Pedro and Orcan for looking up the current situation
in major distros. Let me summarise:
Debian (and derivatives such as Ubuntu):
Directory: /usr/share/sounds/sf2
File: N/A
Fedora:
Directory: /usr/share/soundfonts
File: /usr/share/soundfonts/default.sf2
OpenSuse:
Directory: /usr/share/sounds/sf2
File: N/A, but can be set by user through a SOUNDFONT_FILES
environment variable
Mandriva:
Directory: /usr/share/soundfonts
File: N/A
Maybe reach out to distro maintainers and ask for their opinion on
the matter?
And btw, what about Mac / Windows / other platforms?