My favourite armour is the Dark Brotherhood's Shrouded Armour/ancient.

I absolutely love the look of this armour; I feel as though it gives a really nice assassin feel. The colours and model of the armour also please me.

Being a sneaky nuisance/assassin type character (although, I sometimes alternate), the individual pieces of the set match my play-style very well.

The shrouded hood is also my favourite piece of apparel in the game. The sneak enchantment is decent, it goes with most armours/clothing, and it pleases me aesthetically. It also looks good if playing as a vampire.

Edit: I'm referring to armours from vanilla Skyrim (DLCs included).

My favorite kind of depends on the character. I'm thinking you want to know what I personally like, here goes.

Glass armor is beautiful but only the male variant is my favorite. So I usually put it on my male companions.

The Nightingale armor is nice for looks and enchantments and it has a cape! I love capes! It looks good on males and females.

Bonus modded armors: Calyp's Ceremonial Bosmer Armor and Maty's Mythril Armor (I miss mythril from the previous ES and this is gorgeous).

Vanilla - Nordic Carved or Ancient Nord.
Why?
Because they're sixy. Because they're Nordic. And because they are sixy.

Modded - Haven't decided yet.

Dawngaurd Heavy Armor.

1. It does not have overdone boobplate, like Wolf Armor.

2. My character is usually the only character in the Game wearing the Armor outside of the faction headquarters. Nordic Plate is actually a very common Armor in the Game. If a Player has the Dragonborn DLC, Nordic Carved is usually found on Bandit Bosses, not on Heroines like Frea.

Having stated this, I do like Ancient Nordic almost as much as Dawngaurd Heavy, and I will aquire Azhidal's Relics for creating End Game Weapons and Armor.

EDIT Favorite Modded Armor is Silverlight, I have enjoyed the Armor since Oblivion and even added it to Morrowind. I even found an esp on Nexus that makes the Armor into Clothing with Enchantments from the Arcmages Robe.

Really? I think Glass armour looks great on both sixes,

I agree but I just think it looks better on males. It is the textures? colors? that are slightly different that makes it look better.

Standard armors; nordic carved and dawnguard light/heavy.

Mods; http://i.imgur.com/XHaD1GA.png from zzjay's wardrobe.

Scaled armor with leather bracers, vampire boots, and a mage hood. I like to look inconspicuous while traveling. Maybe swap out the armor for guard armor of a hold depending on the character.

Ebony Mail + Nightingale Boots/Gauntlets. Favorite Armor Combo. What I'm using on my current character. Although I'm probably going to switch out Nightingale for Ebony so I can enchant.. but that's a discussion for another topic.

Ebony Mail is the best looking armor, for sure. Way better than the ugly Ebony Armor.

Stalhrim or Ebony because I like the way they look.

My favorite vanilla armor is elven armor. It looks great (most important) and has decent stats.

Elven Gilded armour shocked me when I first saw how strong it is.

Gosh, so many to choose from! First off, I'm not giving any considerations to helmets because we don't use them on primary or companion characters.

Novice mage robes (I know, not armor), but with scaled boots and bracers.

Fur - variants 2 (fur on the shoulders and bare midrift) and 4 (full coverage) with hide boots and bracers.

Imperial light armor & bracers with hide boots.

Scaled armor - normal on women and horned on men.

Steel plate - for heavily armored companion women.

Carved Nordic - for heavily armored companion men.

For a lark, Savior Hide with scaled boots.

I have never worn a complete armor set. All of my preferred "looks" for characters consist of mixing and matching from many different armors ... most from mods.