I pick armor on aesthetics, not quality, so Cronach, my orc warrior, is a level 29 running around in Banded Iron armor. It just looks so... adventurous. He wears an Orcish helm (because they're badass, and he needs some Orc gear), and I prefer the nord steel gloves and boots.
For less combat oriented types, I like the nightingale armor (Cape. Aww yeah), ad the black/dark gray vampire armor. I play on Xbox, so it was nice to finally find a piece that looked right for an assassin and I could enchant.
Also...
Do you have the shadow warrior perk? That sounds more like the effect from that than the armor. At least, I haven't noticed that with vampire armor.