In addition, I would like to ask whether I'm missing anything. I know I'm missing the Case and Optical Drive, but I have those from my old computer, but I'm not sure they're compatible.
I have an unidentified case. All I know is that it's an ATX mid-range tower that can hold a Pegatron Violet motherboard.
I also have several Optical Drives. I have absolutely no idea what type they are.
Your build seems fine, the motherboard CPU and ram are all compatible. Your PSU is also plenty for your needs.
I cannot help you with the case, as there is little information however if it can fit an ATX sized motherboard you won't have a problem. (I know how you feel, i have a prebuild with a no name case at the moment).
However, if you are re-using the Optical drives (or old hard drives for that matter) you need to ensure they have SATA connections (All do nowadays, however some of the older ones use the IDE format and you will not be able to plug these into that motherboard).
If they have connectors that look like this: http://www.frontx.com/pro/c203_018p2.gif you cannot reuse them
If they have connectors that look like this http://www.sierra-cables.com/Cables/Images/SATA-Signal-... you will be good.