I have it for the Xbox 360 and it despends what game you're playing. All I ever play is hardcore team, hardcore search and free for all. So:

Hardcore team/Search-
G3 auto silenced, claymores, Uav jammer, dead silence, silence pistol or golden eagle.

Golden uzi same as above.

G36c with red dot or acog, claymores, Uav jammer and deep impact.

Golden dragonov sniper, claymores, overkill, deep impact and M4 carbine red dot.

M4 carbine, grenade launcher, slight of hand, deep impact. Silenced pistol or gold eagle.

Free for all isn't hardcore so I usually always put stopping power on with deep impact or martydom. Will have one class Uav/dead silence or slight of hand so I can creep round on people. I have a modded controller so get a selectable upto 18 shots/presses a second on single shooters like snippers, hand guns or G3 etc. Brilliant creeping on those camping in houses and smashing them with golden eagle before they even blink or rapid fire silenced pistol in the back. G3 is so smooth, steady and accurate just needs to be auto, mine is.

Again golden shotgun with the pad and slight of hand is cracking on confined maps then a machine gun baretta handgun in case you get caught out. M16 with red dot probably is the easiest and best gun in the game though but I prefer ze germans like mp5 and g36c.