I don't have any 'specialty' rulers other than two triangles, 45º and 60º. I've never encounted a shape that I can't cut accurately without one and I hate 'single-task' tools. As for favorite brand, it has to be Olfa Frosted Advantage...thinnest lines, non-slip, most accurate cuts, easiest to see through on all fabrics. Omni-Grid and Omni-Grip drive me to distraction so I gave them away almost immediately.
Keep the ones that work best for you and get rid of the rest. I'm sure they'll be much appreciated by others. And, in my experience, using the same ruler during cutting does increase accuracy, all else being equal.
Last edited by ghostrider; 01-23-2015 at 10:40 AM.