Number 8, because black and blue together has been a favourite theme of colour of mine for a long time, even before I started to build PC's. My current PC is orientated around black and blue, MSI Motherboard, MSi Graphics Card, and black and blue Avexir Core RAM.
Although the number 8 case lacks a window it still looks very aesthetically pleasing from outside, it looks quite simplistic and minimalistic which I desire in a case. I would that case would be a fine addition to my builds.