I suddenly realize that every graphic novel that I have recomended is in black and white. To add a bit of color, I will mention the truly grisly
When the Wind Blows (1982), which descripes a nuclear attack on Britain from the point of view of an elderly couple.
Review:
http://www.forbiddenplanet.co.uk/blo...he-wind-blows/
Oh, and
Hideshi Hino is worth checking out too - plenty of gross-out, though.