I have recently purchased a Western Digital My Book Live 2TB NAS drive and am in the process of setting it up.

Here is my current setup/equipment:

Desktop PC (windows 7) - Freeview Satellite recording through Windows meda Centre
Desktop PC (windows 7) - parents PC for work mainly
Laptop (windows 7) - parents for email internet etc
Laptop (windows 7) - girlfriends for university and personal
3 Android Smartphones
Panasonic Viera v20 - dlna streaming
PS3 - dlna streaming

I intend to use the My Book Live as a backup drive for all PC's/Laptops and also to store media (recorded tv, itunes library) for access by all devices.

I have currently copied all documents and pictures to the drive as a backup and am in the process of doing image backups of all system partitions onto the drive.
I have been playing with options for media streaming and I have posted in the HTPC forum about the media streaming aspect.

From here i would like to figure out how to organise my files between the NAS and all the computers.

Ideally i would like for the parents work files to be accesible offline on both their laptop and their desktop with remote access and backup provided by the NAS. So when a new file was created on the desktop it would automatically copy to the NAS and then when the laptop was next used a copy would be created on the Laptop HDD also. (vice versa also) So i imagine some synchronising software would be in order??

Any advice welcome.