My Christmas present arrived today - the FasTTrack mitre gauge and fence with an adjustable stop. It is featured on p. 28 of the current Fine Woodworking (#168). It is a beautifully engineered product, which, in theory, can yield angles accurate to 1/100th of a degree. Such accuracy is needed when you are cutting the mitres for polygons. Of course, to achieve such accuracy in practice you need to be certain that the table-saw's slot is perfectly parallel to the blade, and that the slot itself is dead straight and has perfectly parallel sides.

I am very happy with my US$150 purchase. I ordered it online on the 22nd; it arrived 8 days later, and I was charged only US$30 for freight (the standard charge for American customers). Seeing that the actual air mail postage cost US$36.50, I got a bargain.

With reference to the previous thread on shoulder planes, I would much rather have this mitre-gauge, which yields a previously unobtainable level of accuracy, than have half of a Clifton shoulder plane, which would be nice to own, if money were no object, but which can easily be done without.