BEST ARMORS please?

The best is +5 Full Plate (AC -4), but it is kinda "temporary".

Well, it depends on what you want....
For just AC bonus, Armor of the Heart (Full Plate +3) gives you -2 AC, and nothing else.

If you like bonuses....
Gorgon Plate (Plate +4) gives you -1 AC, but also +25% to acid and fire resistance
Red Dragon Scale gives you -1 AC, and +50% fire resitance.

The best leather armor is the Black Dragon Scale, which gives you 1 AC and +50% restiance to acid...
Aeger's Hide is pretty good, gives an AC of 3, but also +15% resistance to fire, cold, and acid.

The best leather overall is the Human Flesh +5, which gives an AC of 3, but also a -4 bonus to all saves and also 20% resitance to magic. BUT, you have to be evil to wear it.

Bladeslinger Chain is great too, it can be worn by dual-classed mages to grant an AC of 1, and they can cast spells from it too.

I'm very sure the Red Dragon Scale will provide you with -2. Anyways, if you are going for low AC take this one (the only Red Dragon I found so far is, however, very tough, way tougher then the shadow dragon), because it does not, I repeat, DOES NOT, count as magical so you can add some fancy ring or cloak or amu or whatever of protection to go even lower in AC.

Where did you come across the "Bladeslinger Chain"?

The best armor is probably the Red Dragonscale (discounting Drow Armors such as Drow Elven Chain +3 (VERY NICE) and Drow Full Plate +5) The Red Dragonscale is only AC -1, but it doesn't count as "magical" so you can use the Ring of Gaxx, or a Ring of Prot+2 etc. with it to reduce the AC further.

-Arkenian the Golden

++SPOILER CONCERNING BLADESINGER CHAIN COMING++

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In the elven city of Suldanessellar. Be VERY vigilant in searching bodies for loot.

The ring of Gaxx CAN be used with every armour in the game. This also goes for every AC lowering item which does something else aswell, for example Cloak of the Sewers, Ring of Earth Elemental Control. This way I've got my Paladin down to -13 without a shield.