I've recently completed a new Mac application, ImageIngester, designed to import images with maximum safety: It makes two copies, one a backup on a different drive. It can automatically convert raws to DNGs if you like, and it can rename files according to your specifications, which can conform to DAM-Book recommendations. If you import JPEGs, it automatically verifies them by reading and decompressing to ensure that there are no errors. After optionally running DNG Converter, it resets the modification time of the DNG to match that of the original image file.
ImageIngester is for import only--it never alters any images or tampers with any metadata.
I like the idea of keeping the original raw on the backup device, while automatically creating DNGs for me to use as working copies. However, if you want raws as working copies, converting to DNGs later or never, you can use ImageIngester that way as well.
To read more and download (free; Mac OS X only): http://basepath.com/ImageIngester/