This was my 'getting nukes' class in MW2:
M16A4 (the 3 burst assault rifle)
-red dot sight
Spas-12 shotgun
-extended mags
Semtex
2x stun grenades
Sleight of hand (pro) [Or scavenger (pro), both are good.]
Stopping power (pro)
Ninja (pro)
Basically just be sure to always be aiming down sight when you want to shoot. Hipfire is suicide. Crouch whenever possible, smaller target and a bit more stable aiming (so i've heard). NEVER just willy nilly run around a corner, ALWAYS aim down sight and be prepared. And the #1 way I would find enemies was listening to footsteps, so headsets help.