I agree that basing it on Jesus is a little silly, but after all, that's when we started counting. I prefer just to think of it as "2007 years since we started counting." Sure, there were other counting systems, but this one is pretty ingrained. There are billions of written records with this dating system on it. If we change the system, we'll have to also keep track of which system something was dated in... end result: we don't get to drop A.D. after all.