Personally for a light medium/long range weapon, i would go for some kind of G36 varient, preferebly the G36C for more medium range. The FN-P90 is one of my personal favorite guns, great for medium to short range. I can see 2 guns, say a long range then a shorter range SMG type weapon, but 3 is way too many to lug around.
PS. My avatar is a picture of a G36C
