Here is another sewing tool I just can't live without...the June Tailor Press-Mate ironing board cover. The entire top is printed with 1" squares, a yardstick strip up the middle and along the end, and it has printed circles with 4-6-8-10-12-14" diameters!
It can be found online here and here. Both places have good prices too. If I remember correctly mine was around $30 at Fabric Depot.