When I read the question I laughed and was about to answer "Which one?" but reading the replies, it looks like most of us have more than 1 machine going at a time.
At the moment, 3 of my machines share a long Ikea table. I am currently mostly using my Janome 4900 so it is in the center on one long side. At one end, is Mabel, my 301A who has the most important task of sewing zippers in pouches and totes. I love her tiny sewing foot--even better than her zipper foot. And at the other end is Brunhilda, my 1980's Viking and my latest addition. We still aren't very well acquainted but I try to sew with her every week or so.
My Pfaff is on the floor, waiting for a service. Having tension issues with her.