Me personally
Mk. 20 Superior Combat Assault Rifle [SCAR]
Attachments: Gauss, Reflex
Armor Module: Nano Enhance
Stealth Module: Tracker
Power Module: Point Fire Enhance

Gauss Attachment takes some serious practice for it to be useful... it kills in 2 shots, or 1 to the head. If you are low ping, you'll be able to get kills with it. If not, don't bother. Grenade launcher may work better for you. I just like gauss because it's difficult to use, and therefore more of a skill weapon.

General tactic tips for loadout: stealth from cover to cover, observe the battlefield while in cloak, support team mates. Best not to use Gauss unless against gunship or ranged opponents (takes gunship down in 5 shots). Will not help if the enemy knows that you're there. Use from a distance.

Tracker helps find enemy locations if they try to outmaneuver me. Nano enhance will improve my ability to fight for longer durations when fully upgraded (gives faster recharge for energy in addition to health, good for FFA gametypes). Point Fire enhance helps keep the weapon accurate when firing from the hip.

Might create a loadout dependent on these three modules: Armor Enhance, Stealth Enhance, and Mobility Enhance.

Is the guass attachment any good? It couldn't be anything like the gauss sniper eh? Lol.

I use:

Scar
Laser Sight
Hologram Decoy
Armour Enhance I believe
The one that makes you hidden from Radars
and Weapon Pro, cos hell that's what I am!

Then again this should change soon cos I'm still a pretty low level.

I like keeping to the edges, back to a wall runing around crazy spotting someone take them ut and quickly checking my surroundings cos when people hear you shoot they will come for you. I tend not to use stealth, it's too much of a drain before a battle. (:

Not going to post all my set ups but Covert Ops is just about the only Stealth module I use. Ive already been accused of hacking because I find people with sound whoring.

I found a loadout that seems to just create indefinite lethality, a guy had 39 kills with this setup.

Any weapon with which ammo is common and plentiful (SCAR)
Modules
-Energy Transfer
-Cloak Enhance
-Mobility Enhance

Essentially, your energy is limitless if you keep on killing.