Not very, actually. Above is a galaxy size comparison chart (by Rhys Taylor), showing, to the same scale, a selection of galaxies that we know about. It’s a visually stunning piece of work, and really shows how huge galaxies can be, as well as how diverse. Click the image to see it in full detail, or head over to rhysy.net for some zoomable images.
If you could pick one galaxy to live in, which would you choose? Onwards!