If you are asking about what attachments to use please state what mode you play and how you play, i.e; do you rush or sit back (aka camp?) If you are asking what you should permanently unlock it would be nice to know; A) have you already prestiged? If so what have you unlocked B) once again, how do you play? C) if this is the first time you've prestiged you should unlock ghost permanently as if you take an extra create a class slot you're going to lose the default class with Ghost.
As it stand I feel like I'm trying to solve a case by peoples' vague posts.