What is the highest armor class attainable in the game? Are there rings that give more than plus 3? Just curious - trying a playthrough with a single guy and wanna get the best defense I can.
Defenses come in various forms, so there is no one answer. For AC, elven chain or mithral shirt are good choices if you have a high Dex and can enchant them, or some form of heavier enchanted armor for low Dex. Ring of protection goes up to +3 if you rely on finding them, but a high level cleric can forge a +5 ring I believe. An amulet of natural armor stacks with regular armor or bracers of armor. However, if you use all of your item slots to max out AC, then you may have to give up boosting saving throw bonuses, spell resistance, or a periapt of wound closure, all of which are also forms of defense. This is not mention items to boost your stats, which can improve AC, saves, or effectiveness of various abilities. Various items, in particular rings, can protect you against various forms of energy damage, or other magical effects. Lareth's ring is one I like to have on a solo character.
It does somewhat depend on the character you play as well- fighters can use the best armor and shields while monks would have to use bracers, rings, and amulets of natural armor. Gloves of Dexterity would also help their AC as well I believe. I just tested the purple elven chain with Hero's Shield and Gloves of Dexterity +6 on my fighter with a 18 Dex and got to AC 28...
The highest I've manged to get is 44 on my Rogue/Ranger (Yep not my Monk!), could probably hit 45 if I used Haste... and even higher if I had Combat Expertise and could cast Righteous Might. If anything, this should give you an idea on what kind of AC modifiers to stack on. But generally DEX based characters are the key to hit stupid high AC values. Monk's are notable since they can hit high AC values with minimal effort through their WIS to AC bonus.
One thing to remember is no matter how high your AC is, if they roll a critical it hits you and we all know TOEE hands out crits to the bad guys like they were candy.
