isolated vs non-isolated power supply

[VojislavM]

Is there need for 5V and 9V power supplies to be isolated?

isolated suggestions:

• http://uk.farnell.com/xp-power/jcd0424s09/dc-dc-converter-4w-9v-dip-24/dp/2065194
• http://uk.farnell.com/murata-power-solutions/spm15-050-q12p-c/dc-dc-conv-medical-15w-5v-3a/dp/2470131

non-isolated suggestions:

• both for 9V and 5V: http://uk.farnell.com/texas-instruments/ptn78060waz/ic-isr-3a-adj-o-p-smd-78060/dp/1109705

if we put isolated power supplies, the whole devise will be isolated because Ethernet data lines are isolated with internal transformers

[VojislavM]

Because of the noise it is better for device to be electrically isolated, so isolated power modules are way to go.
New question is where should metal conductive casing be connected?

[VojislavM]

We will support both options, see #1