I have recently added Marti Michell's line of rulers and templates.  Marti refers to it as the Perfect Patchwork System©:

"It's our combination of templates, books and patterns that results of perfect patchwork quilts. We won the Best New Product Awards with our first sets of templates, A through D. Since then we have created new template sets each year – We now offer Sets A through S (and we're working on T now). We have also added several pattern-specific sets, such as Drunkard's Path, Giant Dahlia and Dresden Plate to our template line, and offer a variety of books and patterns so you can make perfect patchwork quilts in a variety of favorite designs.

"Rotary cutting and strip techniques revolutionized patchwork, and From Marti Michell Perfect Patchwork Templates take the revolution a step further. Their revolutionary corner concept by Jane Hackworth Gruchacz means cutting pieces that match perfectly–no pinning or guessing required, and no more "dog ears" ensnared by the throat plate or shadowing through light fabrics. The thick acrylic templates mean you can rotary-cut multiple layers of fabric at one time. Combined with perfectly-sewn 1/4" (6mm) seams and the block patterns in the Encyclopedia of Patchwork Blocks, Volumes 1 through 4 and 6, you’ll be making more quilts, more easily and more quickly!"  http://www.frommarti.com/our_products.shtml