My two favorites are the Quilter's FabriCalc (love that thing) and the SideWinder (winds thread on the bobber). I think that it is feasible to assume that if you use it it's NOT a gadget - it's a necessary tool! I do not consider my ergonomically designed Fons and Porter seam ripper a gadget. Mine is dull. It is a necessary tool to my sewing. Same goes for rulers. I have a bunch - they are gadgets. My Omni Edge is a tool. That and a purple steel ruler with rubber on the backside so it won't slide all over the place. Whatever we use is different than whatever we have. I have a few rulers here I don't even know how to work them. That's a gadget. But isn't it fun to have those sitting on your work table and while you are sewing away, your eyes go to it and say "Why did I need that so bad. I don't even know what it does, how it does it or why it does it! But I had to have it."
But then in a moment of sanity, we will figure out what it does and wonder how in the world did we ever get along without it! Edie