I have no idea what the drives are going to be used for, but I do know this:
Everyone expected Apple to increase the size of the iPod even before the Toshiba drive announcement. It was a common expectation that as time went on, the HD sizes would move up.
They have obviously bought way more drives than they would ever sell of a 60GB iPod. So what are they using it for?
iMac? Doubtful, but still possible if absolutely needed
Tablet? Jobs hates tablets
iBook or PowerBook? Possibly if they make one really really small
maybe an Apple digital camera with built in HD, sure would beat those memory stick and CD-ROM cameras. Would it be motion video as well as stills, I dont know.
Thats my bet, Apple has a lot of experience with tiny drives, and they have growing experience with CCD chips (iSight). They may attempt to smack sony pretty hard in the digital camera space.
Back to what I originally said: It was common knoweldge (assumption) that Apple would do a 60GB iPod. Apple wouldn't have been too upset with Toshiba over that mixup, everyone expected it. HOWEVER: Apple was furious, so says ThinkSecret. Think about it: No matter what they are for, they are not for the iPod. No one knows what they are using them for, but we can assess the following:
1) Its a mass production device, as in really really expected to sell
2) Its very hush hush
3) It needs 60GB of disk space, and we dont have many stand alone applications which do!