The usual red and black because they're my two favorite colors. xD Wait, what theme are you referring to? The actual PC, or do you mean the desktop? If the latter, mine is currently light blue with a Minecraft background on the left monitor, and a background of a the local bin collection schedual on the right monitor because I would never remember otherwise. xD I usually go with a black theme on the desktop, but Windows 8.1 kinda sucks for that. I managed to tweak it so I could get such a theme, but for some reason it decided to bug up, hence the change. I'll probably go back to black eventually.