most of my favorite rulers are from Wrights. nice thin lines; markings for 1/8th inches; not overly expensive; most are good for more than one thing; they're just great. i'm especially fond of their triangle rulers. the easiest on the planet (for me, anyway. i won't criticize anybody else's favorites.)
i recently forked out the bucks for an Olfa frosted ruler. may i say .... oooooooooooooooooooooo is it nice! also nice thin lines; 1/8th inch markings; easy to read; doesn't slide around all over the place (but doesn't pull the fabric out of wack); and has easy to use markings for all the most common angles - including 15 degrees. it wasn't cheap, but i didn't have the sense to hunt for it with a big discount coupon in my hand. :roll:
still ... worth every penny.