I Would Have to say modern. Though I would like more of a selection of green uniforms With modern style heads.
I swear in my experience green is the second most prevalent color after that dusty tan. Past that it's probably black, then sandy light, then arctic white, then assorted other colors.
It seems to me that most sets are either not green or time periods that don't fit with modern themes. I hope the new COD game has more than desert fatigues. Some jungle warfare would also be cool, based on the modern era.