Using SWFObject to only show the flash movie on recent players got around this. Users with old players just see an imagemap with js rollovers. Then I discovered that more recent macs (Safari 2+ on 10.4) didn’t play the rollover animations correctly. It seemed that the browser was calling the onmouseover and onmouseout events simulaneously. Arrgh! Fixed it with some js broswer detection – something I try to avoid doing unless my back is against a wall.