I also use iKlear. I was weary of buying a special "screen cleaner" solution. However, I really like that it cleans finger prints and dirt off of the case, keyboard, trackpad, magic mouse, etc. I like that it is non-toxic, non-alcohol based, and that it works. It was worth the small $$ ($25, I think? something like that) and comes with the spray, a cloth and some travel wipes that can be thrown into the bag for having on hand when it isn't convenient to use the spray.
You broke down and put some extra money into your computer; it's worth putting an extra few dollars in to keeping it looking nice (because really, thats all the screen cleaner does; makes it look nice and get rid of distracting (because they don't look nice) finger prints and smudges.