>Admittidly, I haven't looked into them too much since it would just be a geek toy for me, but I haven't found any handhelds with hard drives. They seem to all use some sort of flash media. Since MP3 Players are getting hard drives and still staying pretty light (Creative's Nomad), it seems like they could add a hard drive to a handheld computer. Are there any? Or any plans for any?

Do to the nature of handhelds (low power, needed to be rugged) you won't see many hard drives. Flash cards are great. They work just like a disk drive. Plug them in and you get a new folder off of the root of the OS.

That said, IBM has made a microdrive for Palms
http://www.storage.ibm.com/hardsoft/diskdrdl/micro/index.htm