I think I've decided on a paint scheme for my Imperial Guard forces. I really didn't want to paint another green/brown army because all of my armies so far (Space Marines, Orcs & Goblins, Skaven) are painted green and/or brown and because so many Guard armies you see on the internet and in GW's printed materials are in those colors. So I knew what I wanted them not to look like, but I didn't really have any idea what did want to paint them like. Games Workshop had an article on their site showcasing various armor camouflage schemes, and on the last page I found this one:
It is officially called Mars Pattern XXI, but I imagine regiments fighting on any red planet could use it. There is a little bit of green in the camo, but not enough for it to be a major color. I'm not sure how I'll paint the infantry, but I imagine it will be some sort of grey/red combo.