What is the toughest armor that you can obtain in Oblivion?

If you mean tough solely as in highest armor rating, then it's Daedric. If you're looking for the "best armor," that depends on your personal taste. You can look http://uesp.net/wiki/Oblivion:Leveled_Items#Armor for every enchanted piece of armor in the game.

Highest health and AR is Madness armor, from the Shivering Isles. Amber, with 100 light armor skill, offers the same protection, but has less health.

The maximum armor rating is 85, which is very easy to get. So it boils down to as you say, toughest - meaning durability.

Properly enchanted, a peasant blouse, green silk skirt, green satin shoes and a copper amulet can provide an armor rating of 85. What makes this outfit superior is that it is totally indestructable. Oh, and it looks nice too (if you have the figure for it of course). :twirl:

Ever indestructable clothes. Yay.

I do that on my pure mage characters, but when I'm playing as a fighter, repair hammers are a small price to pay to save four enchantment slots, and at 100 armorer, durability isn't really an issue.

Just like Acadian said, when armor is properly enchanted it gives the maximum armor rating. Haa-Rei wears full leather armor (He swapped the leather helmet for a zealot hood) and he has an armor rating of 85. Durability can be a problem but a high enough armorer skill can soon solve that.

Well, I guess you could argue: Estchucheon of Chorrol, Necklace of Swords/Amulet of Axes, and Ring of the Iron Fist. Yeah, I dunno how to spell the name of that shield, but you get the idea

I think that once you're ridiculously high-level, The Divine Crusader's armor is the best overall, stats-wise. (It levels with you).

Also: this is my 400th post

Been playing over 1000 hours and only EVER use leather armour.

skills/stats/% in this game I have found to be quite unimportant.