I consider myself a bass player since that's what I enjoy the most and that's what I play in my heavy rock band. I was a music education major in college so that combined with becoming a band instrument repair guy while apprenticing at a local music store over many years pretty much allowed me to learn how to play all the winds. Now obviously I'm not performance quality on most of them, but I fool a lot of the customers when I play test their horn. I was a tuba player through high school and college as well and still play it on some of the Beatles tunes we do, as well as trombone.
My primary role in the Beatles band though is auxillary percussion. As mentioned in the "instruments owned" thread, I have a whole box of things to hit, shake, rattle and so on. I also trigger samples for things like crowd noise in Sgt. Pepper's, tambura drones, reverse cymbals, wind, birds and you get the idea. I do play bass, guitar and sing a little on a couple songs to prove to the audience that I'm not just the Linda or Yoko of the group.....or at least that's what I tell myself when I lie awake at night.