I use ultra fine point Sharpies myself and I've never had a problem. They do have a relatively hard point, but as long as you don't press too hard, you shouldn't have any problems. I do think it's fairly hard to screw up a cd with a pen, though. I had a rather ignorant friend who used a ball-point pen to write on a cdr. He used enough pressure that you could actually read what he had written in the colored dye stuff looking at the bottom of the cd. Despite the obvious damage, the cd still worked just fine. I wouldn't recommend it, though.