Hey i'll be posting a few classes that are useful.

Stealth Assault

- Any Primairy weapon (silencer)
- Stinger

- Any equipment
- Any special grenade

- Any blue perk (exept from OMA, as One Man Army replaces your secondary)
- Cold Blooded
- Ninja

- Any Deathstreak

Anti-Air

- Any Primairy weapon (any attachment)
- Stinger

- Any equipment
- Any special grenade

- Any blue perk (exept from OMA, as One Man Army replaces your secondary)
- Cold Blooded
- Any yellow perk

- Any Deathstreak

Knife-alicious (knife class)

- Any LIGHT primaire (silencer)
- Any handgun (tactical knife)

- Throwing Knife
- Any special grenade

- Marathon
- Lightweight
- Commando

- Martyrdom

There are other ways of creating a knife class, you can for instance change lightweight to cold blooded, which will take care of you never show up on the radar, and with ninja pro you don't appear on HBS (heartbeatsensor) and your footsteps can't be heard, those mods on the class are nice, the one above is the standard one. Feel free to use any of these, experiment with 'em.

2dn Knife class (the one i use ATM)

- Any SMG (silencer)
- Any handgun (tactical knife)

- Throwing Knife
- Flash/Stun

- Marathon
- Cold Blooded (Pro is helpful, no red name)
- Ninja Pro

With this class i never ever show up on the enemy map, which does help.
Cold Blooded Pro is very helpful:
- No exposure with enemy UAV
- You won't be attacked by enemy air-support
- [PRO] no red name when enemy looks at you, no red crosshair, this will let people hesitate or just ignore you quite often.

Ninja Pro:
- Not on HBS
- Silent Footsteps

Primairy has to be a SMG because they are the lightest, this will lower your speed loss of not having Lightweight.