If you are going to put any lights inside, please please, for the love of God (of war), use white light, no matter the overall color of the build. White light makes every color looks like the color. Red light will make everything look red... For example:
Oh i'm gonna be using RGB LEDs, so i can change color from whatever to whatever. White for showing off, and whatever color i go with for scheme.
If you are fine with a tiny bit of soldering I highly recommend getting the cheap rolls of LEDs as opposed to the ones that are specifically made for computers (like BitFenix alchemy strips or NZXT hue, unless you want the extra bells and whistles you get with the hue). It is a hell of a lot cheaper to just cut the lengths and solder some wires, also its another little thing in your computer you can be proud to say "I did that all myself".
I solder for fun. Arduinos are a hobby of mine. I like sticking them in 3d printed objects/projects.
Off-topic: check out Objects in Space then... Arduino and soldering for fun is actually a requirement...
https://forum.teksyndicate.com/t/objects-in-space-unique-is-an-understatement/101045
That looks like a lot of fun if it actually plays well. I might buy it just to check it out.
I especially like the whole 'make your experience' it has going on for it.