Which second instrument would be most valuable to a drummer? I often see some folks on here saying that a drummer will be much more useful to a band if he can play another instrument. Like what? And in what kind of situation would it be useful to the band?
Knowing how your bass player thinks and what they like/dislike is pretty damned useful. I learned my way around the keyboard and I'm pretty glad I did and now I'm picking up bass. I don't really know if one is going to be that much more useful to you than another. Just about any instrument is going to be helpful so I would pick the one that is most interesting to you. You'll get more out of it that way.