Does anyone have a list of all the usable song formats?

Since .SPC is possible.. what about others?

Vanilla Doom supports only MIDIs (and MUSs, but MIDIs are superior). Support for other music formats is specific to particular source ports.

scifista42 said:

Vanilla Doom supports only MIDIs (and MUSs, but MIDIs are superior). Support for other music formats is specific to particular source ports.

What's a MUS?

edit : Are .s3m files supported?

http://doomwiki.org/wiki/MUS

They're basically crippled MIDIs, obsolete nowadays.

It should be noted that vanilla Doom converts MIDI to MUS internally, so there's no advantage in using the former for a pure vanilla release.

scifista42 said:

Vanilla Doom supports only MIDIs

thesecondcomingdoom said:

edit : Are .s3m files supported?

Not in vanilla. But they're apparently supported by ZDoom, therefore also by GZDoom and probably Zandronum too, and maybe some other ports. So it really depends on your intended target compatibility of your wad, respectively the compatibility of your wad will depend on your choice of music format.

Da Werecat said:

It should be noted that vanilla Doom converts MIDI to MUS internally, so there's no advantage in using the former for a pure vanilla release.

Preserving metadata, which can include copyright attribution, is definitely an advantage.