Ooops, sorry, check that. Just as it finished booting it happened.
But then I noticed I have another copy in /system/media/audio/notifications. Not really willing to rename that one, as I'm sure it's the one I use for gmail and other legitimate notifications.
Sorry guys...not sure if deleting it would matter, but I suspect that's not the "droid" we want.
EDIT: FOUND IT!!! In /system/media/bootanimation.zip, open up desc.txt (basically this is the "script" that arranges the startup animation) and the person who wrote the script COMMENTED IT VERY WELL. Basically, head down to:
and the comments explain that the "s defines a sound for a part; sounds will be loaded from /system/media; oggs with loop points will loop automatically; only one sound will play at a time; timing is driven by the part, not the sounds; IF YOU WANT NO SOUND, LEAVE BLANK"Code:# droid p 1 7 01_droid s Droid.ogg
Oh, what a pain -- looks like in order to edit desc.txt you need to extract it first, then reinsert it in the zip. Ah, not worth the trouble for me, but commenting out the "s Droid.ogg" line in file should do the trick!