I use
Class 1
Primary: ACR + Silencer + Heartbeat
Secondry: Spas 12 + Grip + Extended Mags
Perk 1: Bling
Perk 2: Stopping Power
Perk 3: Ninja
Equipment: Claymore
Class 2
Primary: Mini Uzi + Rapid Fire
Secondry: G18 Akimbo
Perk1: Marathon
Perk2: Stopping Power
Perk3: Steady Aim
Equipment: Tactical Insertion (for sabotage)
Class 3
Primary: Aug Hbar + Extended Mags
Perk 1: One Man Army
Perk 2: Stopping Power
Perk 3: Commando Pro
Equipment: Claymore
Class 4
Primary: Scar H + Heartbeat
Secondry: Stinger
Perk1: Sleight of Hand
Perk2: Cold Blooded
Perk3: Ninja
Equipment: Tactical Insertion
Class 5
Primary: Ump 45 + Rapid Fire
Secondry: Desert Eagle + Tactical Knife
Perk1: Marathon
Perk2: Lightweight
Perk3: Steady Aim
Equipment: Semtex
Class 6
Primary: Barret .50 Cal + Thermal
Secondry: AA12 + Grip
Perk1: Sleight of Hand
Perk2: Stopping Power
Perk3: Steady Aim
Equipment: Claymore
Class 7
Primary: AK47 + Grenade Launcher
Secondry: RPG-7
Perk1: Scavenger
Perk2: Danger Close
Perk3: Commando Pro
Equipment: Blast Shield
There my classes i use all the time, depending on game mode and the opposition