I don't tie mine... leaving it untied allows you to make the thicker part medium rare & have the more-cooked ends for people who prefer it more done.

And actually, if the skinny little tip gets burnt I like to cut it off & munch on it like one of those overcooked, brown potato chips... <img src="http://www.traveltalkonline.com/forums/images/graemlins/Wink.gif" alt="" />