LCD screen

I am interested in adding a screen of some sort to my pc to display info like fan speeds, temps and currently playing music.

I have googled around but there is surprising little information on it. Can anyone point me in the right direction to build something like this.

My main questions are: where to buy, screen sizes, screen types (LCD or otherwise), how it connects to system, power supply, how to program it to give me the info I want.