IMO, icons are useful because they're constant symbols we can associate with different actions. In that sense, the floppy is very appropriate simply because it is nearly universal. Never once in my life have I seen an interface with unfamiliar icons (no text at all) and been able to figure out what it does (I'm looking at you, Mac OS). I think even if you come up with an image that is more true to what is actually going on, such as a picture of a hard drive, you'll cause far more confusion than if you left it alone. Even if people such as myself can identify the icon as a hard drive, that doesn't tell us what you're going to do, it just means a hard drive is somehow involved...
