I like running with a suppressed AR-160, with a coyote and magnifier and tatergrip. My next choice would be basically the same setup, but on an MPX.
I also enjoy using the MK14 with an ACOG, the SR-661 with a 40-14x optic and bipod, and that's the four I'd really choose to use.
For off the wall, I'm a fan of the Dow-12 with flechette rounds, or the PkP with a stubby grip, 3. Optic.
Pondered upon a rainy plateau, with a coal forge, and many dragon.