the best combo i have found is smg and pistol. Another good combo is use a single plasma pistol and have the battle rifle as a backup weapon. if you connect with the plasma pistol one head shot from the battle rifle kills the opponent. i like the covenent sniper better because it has a larger recticle than the human sniper, so if someone comes up on you while you r sniping, it is easier to shoot them with it. also if you treat the sniper rifle like a shotgun in upclose battles (shoot and then melee) it is a good strategy also... just my .02.