I have a couple of Bernina's and the foot I can't do without is the #10 edgestitch foot. The center metal blade guide makes it indepensible for edgestitching, stitching in the ditch, and understitching. I've used it for mini-piping, double-topstitching, tucks, sewing on braid and ribbons and entredeux and probably a zillion other things. And those pintuck feet run a close second!