the more i think about it, the more i feel that a hotsync type method would be the best for syncing up your hdd and empeg. hashing opened up a lot of possibilities. the user should hvae the following choices in the interface:
1) pc -> empeg: all different hashes on pc transferred over to empeg (new songs), all different on empeg deleted (deleted songs).
2) empeg -> pc: vice versa from above.
3) pc <-> empeg: both of above, but without the deletions.

also, do the same with the tags. i commonly change the tags on the hdd, and wish to reflect it on the empeg. for people who edit tags in jemplode, you can reverse the process to sync up the tags on the pc. obviously, a pc <-> empeg sync for tags isn't feasable. if you edited some tags on the empeg, and some on your pc.... there should be a way to do this individually also (or by playlist, etc) so you don't lose your edits.

now for the above, i wouldn't mind to go thru the whole hashing process, just as long as it autosyncs after (so i can leave it unattended).