For me, this depends on what the group carries. Personally, I'd go with a G3. Know it, good weapon, reliable and hefty punch. If the group is fire-team sized or above, it needs a main support weapon system with high rate of fire. I was good with a MG3, but a small group benefits more from a LMG I thin than a GPMG. I'd go with a RPD over the RPK, because I think it's cooler. In case the group gets about squad-sized, I'd go with a MG3.
If all weapon categories are already covered, I'd go with an assault rifle and probably be the squad leader.
