I was pretty active on the guitars.se site, and in my effort to make the merge a success, I'm about to embark on tagging/retagging any unorganised questions from the old site that made the merge. However, before I start, I just wanted to check that the way I am going to tag the questions is the way that everyone else would agree with. My way is pretty much explained by Matthew Read's first answer to this question, applied to bass guitars:
The rest follows from that; you should use acoustic-bass-guitar because it follows the same format, even though acoustic-bass should be unambiguous since there's no reason to add "acoustic" for a standup bass. Likewise, electric-bass-guitar for questions limited solely to electric bass.
I think double-bass should be used as well, just to make it clear that it's not bass guitar. I doubt there will be general bass questions (both double bass and bass guitar), so we shouldn't have bass at all.
Obviously I would be using this standard applied to guitars (electric, acoustic, 12 string etc).
Just wanted to check everyone else agrees with me, I don't want to start off wrong, so that everyone has to go and clear up my mess (not that I wouldn't myself obviously :) )