Ok, sorry for the double post here, but I figured out what kind of loss you may expect based on the over all capacity of the flash card on my digital cam. I multiplied 124.8 4X which brings me to 499.2 for the 512 MB version. Double that for the Gig and I get 99.8 MB. If the Shuffle fallows the same capacity reading as the flash memory in my camera, then this should be fairly accurate.