Actually, I've been thinking about it some more...tell me if I am wrong. Generally speaking:
230v AC --> PSU --> 12v DC --> PC
My monitor has it's own power brick, so its:
230v AC --> LCD power brick --> 12v DC --> LCD
In your example photo above, you're taking your power cord and tapping into the 230v, and then I would be running it through a power brick to the LCD. That's fine.
So I guess I have two options:
1. 230v AC --> PSU and LCD power brick --> 12v --> PC and LCD
2. 230v AC --> PSU --> 12v --> PC and LCD
If I do 1, I will need power brick, but it's easier to tap into AC like you did.
If I do 2, I won't need power brick, but rely on PSU for 12v DC supply.
I think I might do 1.
AM I RIGHT? Or am I not making sense at all?