One thing to add: as a singer, which is first and foremost what I am, the bass is what I key off for a lot of purposes, not just pitching. I CAN follow other things, but if I can only get one thing in my monitors I probably want it to be bass. (Even more than it to be me - as you know, I wear plugs for that.)

Scott Thunes once observed "if you are the bass player in a rock band, you are by definition a moron" - but a very important moron :). (Interview at http://www.cidanka.nl/keneally/stbp0397.htm , by the way.)