Here's another gadget that you'll want to add to your quilting kit.
Celine Perkins of Perkins Dry Goods came up with a tool that enables you to accurately adjust your sewing machine for perfect piecing. Use it to position your needle for a perfect scant 1/4in seam, check the accuracy of your 1/4in foot or mark your machine when a 1/4in piecing foot isn't available.
You may not use this often but it's indispensible every time you do.