I agree with Bobbilinks 100%. I use my Straight edge more than anything and don't get one that is too big! I pick up my 2" x 6" more than any other ruler. In addition to the circles and oval (which I don't have yet but will get some day) I use my curved cross hatching ruler a lot too. I use Rhonda's arc ruler medium size the most. But like having the large and small at my disposal. If you only buy one to start get a small straight edge. When I first started LAing, I found using a ruler very awkward but now I love ruler work. Oh and make sure you have a ruler base for your machine bed, you can't use rulers without it.