Warrior:Dragonplate
Thief:Thieves Guild
Battlemage: Ebony

Also

Barbarian:Orcish
Assassin:I guess shrouded.

By the Nine; I've got so many clothing/armor mods installed that it's hard to pick one. Most of my favs are products of Immersive Armors though.

*Never played a Battle-mage

Warrior: Daedric

Thief: thieves guild

Battlemage: Dwarven or Ebony

NOTE: this is only accounting for vanilla, and not accounting for mods.

My orc barbarian enjoys the feel of the light Barbarian Armor:

http://steamcommunity.com/sharedfiles/filedetails/?id=262492938

and showing the leg portion:

http://steamcommunity.com/sharedfiles/filedetails/?id=262492496

For me it depends on race as I like to choose race related equipment

Warrior (heavy knight) = Nord = Nordic Steel Plate, Heavy Dawnguard (mostly for the helmet) or ebony. Others choices could be Dragonplate or Carved Nordic.

Thief / assassin = Bosmer or Khajiit = elven or glass

Battlemage = Imperial = Dragonscale with Mages Hood (goes really well due to same color)

Edit:
Barbarian = Orc = fur & forsworn with Orcish weapons (dual axes & bow)

Sorcerer (dual destruction & HA) = Dunmer = Hardened Falmer or Daedric (if I was on PC I'd probably go with Ordinator or Telvanni armor)