Step 1: Primary and Secondary
My favorite secondary to a stealth class is the CZ75 silenced. Another nice one is the crossbow, adding accuracy with power. The ballistic knife is cool, but very hard to use.
Step 2: Perks
Ghost is the obvious choice. Scavenger is nice for ammo, as you will need alot for staying alive long. Flak Jacket is bad for stealth, because it is meant for objective rushers, and people who don't like explosives. Lightweight can be helpful, but for rushing. Hardline isn't good, because you should run low killstreaks instead. Recommended: Ghost
Sleight of Hand, or Warlord are good choices. Steady Aim is good if you plan to use a silenced SMG. With Warlord, you can have a silencer and an optical attachment, good for guns like the AUG or FAMAS. Scout is out of the picture. Hardened is as useful as scout for a stealth class. Recommended: Warlord
Ninja or Hacker. Take your pick, an enemy hearing you or you falling victim to a claymore or c4. I would go with Hacker, because the enemy still could not hear you, and you can always crouch. Marathon gets you into the habit of sprinting around corners, which is hard to break. Second chance is for newbs, and Tactical Mask is only good with PRO. Recommended: Hacker
Step 3: Grenades and Equipment
Tactical: Willy Pete, for rushing right past enemies
Equipment: Tactical Insertion, for endless spawn rushing and objective camping.