I don't have a character in Oblivion currently but I'll write about Raven because he was my last OB character.
Raven (
Raimond
Venderaux) almost never wore any armor, he prefered ordinary clothes because they made him feel agile and unburdened.
Headgear: Raven often wore a common blue mage's hood, he always had it on if it was raining but sometimes he put it on in cities as well, when he preferred not to be seen. This hood was one of the few items that he kept almost from his first day.
Torso and hands: Raven changed only a few shirts during his stay in Cyrodiil, one of his first and favorite ones was a common blue & green shirt, enchanted with poison resistance. Later he switched it for a common shirt with suspenders that he bought at Thoronir's. During his battle with Mannimarco he was wearing a patched vest. Regarding gauntlets - except if going to cold places like Bruma, Raven never wore any gauntlets.
Legs and shoes: His favorite pants were enchanted with Spell Absorption, I don't recall where he had found them, but they accompanied him most of the time. At some point he also wore chainmail greaves and chainmail boots and these were the only armor pieces that he liked and made him feel comfortable.
Jewelry: at the beginning he wore a silver amulet and a matching ring but when progressing through the MG questline, he switched his amulet for the Spelldrinker Amulet. He also switched his ring with an enchanted one but right now I can't remember which one it was.
Habits: Raven had a habit that whenever he visited the Arcane University, he changed to a formal University attire, at first he wore common mage's robes, then Robes of the Apprentice, and as he rose in ranks, he wore White Mage's Robes. When visiting Counts, he didn't wear his common clothes but put on something more appropriate, like a green brocade doublet and fine silk trousers.
The only time when he wore full armor, was when he left Cyrodiil after defeating Mannimarco. Since he was going to Skyrim, he needed to be prepared for cold weather, and equipped a full set of fur armor before departing north.