Having some magnetic tools on your bench and using them regularly sounds pretty close to a controlled expirement to me. And my results say it's perfectly safe.
Besides, no need to get all scientific about it for pete's sake. In this day and age where nobody believes in absolutes anymore, EVERYTHING is a matter of personal opinion it seems. But we totally don't need to go there! lol
The fact is, there are respectable techs on both sides, magazines, books etc... which hold to the right and left. Either it's NO magnetic items on your bench, or it's "bah, the little magnets aren't strong enough to harm anything".
Nobody's asking to put a horseshoe magnet on your bench. lol. And speaking of which, I have a magnetic bowl on my bench to toss all my screws in and so forth, it's a fairly strong magnet, I don't keep floppies near it. Come to think of it, I don't USE floppies anymore. So it's a moot point.
Nevertheless, it's still an interresting conversational piece amongst techs.