How to make new partition on SD for media files ?

[IriDium]

Having a separate partition will not make OS install any easier as the whole card will need to be reformatted or at least overwritten.

Also having the OS and the data on the same media is never the best option.

For simplicity, can't you get a check 2G SD card, use that for your OS and keep the Media on the 16GB drive - easier to backup as you could use ext4 or NTFS depending on which is best for your main computer.

Depending on you timeline for the NAS, I'd just create a folder outside of the /home directory (As this would be included in any Xbian backups you create). Once the NAS is up and running install Xbian on the NAS along with your media files.

I think the crucial part is how volatile are your media files? If they are backed up elsewhere then go for the easy option. Otherwise be wary as I wouldn't trust anything critical on a SD card - especially one with multiple I/O and updates.

1) Not the best option as it limits what other devices can read it.
2) If you know how to, then yes and use ext4 or NTFS depending on your main machine
3) Didn't know that option existed - try it an see
4) See above