RDS AK-47, Silenced or RDS Commando, Ironsights G11, and the Silenced FAMAS are my favorite weapons in that particular order. Can't argue with an overall 2.43 K/D ratio result
I'm currently on my 1st prestige, level 24. The FAMAS + Suppressor + Sleight of Hand Pro combo has been quite a life-saver even at a low level.