Quote Originally Posted by soulman View Post
Canon's EOS Utility will do exactly what you want without you having to interact with the card, or its file system, at all. All you need to do it plug the camera into your computer (this may work with just the card too) and use the EOS Utility to download only the new pictures. It keeps track of this, so you don't have to. I have mine set up to put the pictures into folders by date. If you're importing into something like Lightroom, you can do pretty much exactly the same thing, as it too tracks the photos you have already imported. No mess, no fuss.
It does work with card as well. I have it set up that when card is place in computer, one click and it all happens. Once downloaded you can open photos with whatever and they are in date order.