Damnation: I just stuck with a customised version of the N7 armour, as it greatly surpasses the DLC armours in my opnion. How to customise it, however, is entirely up to your playstyle and the difficulty setting.

My suggestion would be:

Head: Kestrel Helmet (+5% headshot damage, +3% weapon damage and +3% shields) or Recon Hood (+5% weapon damage) - it really comes down to which weapon you use the most.

Chest: Kestrel Torso Sheath (+10% melee damage, +5% weapon damage and +3% shields) or Aegis Vest (+5% health, but only this if you have issues with your life total)

Shoulders: N7 Shoulder Guards (+3% weapon damage) or Asymmetric Defense Layer (+5% health). Depends on which area you prefer the bonus in.

Arms: Off-Hand Ammo Pack (+10% more ammo). If you're using Assault Rifle, this is pure gold.

Legs: Life Support Webbing (+10% health) or Ordinance Packs (+10% spare heavy weapon ammo). Depends entirely on how much you use your heavy weapons, and if you have any issue with your life total.

I'm not sure if this is the best for your playstyle, but in the end, it's what I would suggest.

Damnation: It's the best looking armour, yes. Plus, the fact that every other armour's helmet is still on during conversation just annoyed the crap out of me.