Well, with stats like those, you might want to consider other races (or if you want stick with human, but I'm a bit of a nut for Half-Orc fighters myself).
I suggest with Half-Orc, should you choose him, to take the following alternate racial trats:
Replace Intimidate with Shaman's Apprentice (Gain endurance as a bonus feat)
Replace Orc Ferocity with one of the following: Sacred Tattoo (+1 Luck Bonus to all saving throws), Bestial (+2 Bonus on perception checks), or Beastmaster (+2 bonus on handle animal checks, plus whips and nets are martial weapons, which can both be used to great effect in debilitating enemies, as they're normally exotic weapons).
Replace Weapon Familiarity with Chain Fighter (better exotic weapons, though you'll still probably use a 1-hand weapon anyway because Armor masters get bonuses with shields).
Now, normally I'd suggest possibly getting something like Eldritch Heritage feats, but as an armor master, your abilities will be more focused on something else: two weapon fighting and shield bashing.
My suggestion for stat allocation are as follows:
Str 18, Dex 17, Con 17, Int 13, Wis 13, Cha 10. This guy won't be a talker anyway, so Cha is a dump stat. Int and Wis are needed for possible feat entrances and will saving throws.
Feats:
I suggest following several different feat trees for your character if you go half-orc:
Deathless Route (Required feats Endurance, Diehard, Deathless Initiate, Ironhide, Deathless Master, Deathless Zealot) You won't fall down and enemies will have to re-roll successful criticals against you. Combined wiht Armor Master and their natural fortification abilities, you are insanely hard to take down by a critical specialist or weapon master. Not only that, but you already meet the constitution requirements.
Shield Bash Route (Required feats Two Weapon Fighting, Improved Shield Bash, Shield Slam, Shield Master, Bashing Finish** (not absolutely necessary but fun))
Weapon Focus Route (Required Feats Weapon Focus, Weapon Specialization, Greater Weapon Focus, Greater Weapon Specialization)
(you'll want to go with a one handed weapon because of your shield. Now, whichever route you go you'll have to pick a weapon that matches your style. I always like Battleaxe. Simple, effective, damaging, and a great critical multiplier. But you might want higher critical chances and go longsword or scimitar. Or you might want more damage overall and go dwarven waraxe or bastard sword. Will cost you a feat or a trait, but that's your choice.)
Beyond that, as a half-orc, you'll be a front line fighter, so sticking around as long as possible is always necessary for you. The extra other feats you may want are as follows, as well as some obvious choices:
Power Attack, Resilient Brute, Tenacious Survivor, and Fight On.
Fight On grants you some temporary hit points when you hit zero or go below into negatives. It activates before Diehard and the early deathless stuff. Resilient Brute converts a successful critical against you (which will be extremely rare BTW) into half-damage half-nonlethal. Can be a major lifesaver if you're close to death. Tenacious Survivor guarantees that if you should die, a bit of healing and you'll pop back up again. With some negative levels yeah, but that can be removed by some work from a healer. It means that you won't have any of that other nastiness of having to pay for a resurrection spell etc.
Power Attack is self explanatory.
Now, if you go this route, you'll have the following feat requirements:
Deahtless Route - 5 feats (normally 6 but you take endurance as a bonus feat)
Shield Bash - 4-5 feats (depending on bashing finish)
Weapon Focus- 4 Feats
Power Attack, Resilient Brute, Tenacious Survivor, Fight On, Improved Critical, Critical Focus - 6 feats
So, 19 or 20 feats if I'm not mistaken.
You essentially have your unkillable tank. Your strategy will simply be to wade into the action, supported by spellcasters, and hit people until they are dead. You will not fall down, you will not falter, and even when brought into negative hit points, you will still keep going just as if you were at full health. You will even be able to have more hit points (as the half-orc stabilize bonus is useless with the Deathless tree I think, so you can simply take the normal HP bonus at each level).
Equipment: Anything that increases strength and constitution is a major plus. Anything that increases your saves is a major plus.
Other than that, for your magic weapon you'll want the following:
Example: Battleaxe: Adamantine, either +1 Furyborn of Speed, or if you can, a +5 of Speed. This guy is going to walk right up the someone and hit them until they die, so the more hits the better.
For your shield you'll want the following:
Example: Heavy Mithral Spiked Shield (with Adamantine spikes if possible), +X Bashing, . Bashind is a major + as it increases the damage by 2 sizes. Normally, I'd say this applies to the shield itself, but according to the NPC codex, it applies to the Spikes (dwarven barbarian with a bashing spiked shield did 2D6 damage, so it can be a nasty weapon. If your GM will allow it, you can enhance the spikes with Speed as well, so when you attack with your shield, you just keep whacking.
For your armor you'll want the following:
Example: Adamantine Full Plate, +X, and Expeditious, so you can get stuck in as quickly as possible. Other options would be Titanic if you wanted, for the size bonuses, but that's not necessary. For armor, you'll simply want as high a + as possible, and Adamantine no matter what. Damage Reduction stacks, so it's damn necessary.
Normally, other people would suggest Stalwart Defender. I don't. To get those bonuses, you give up too much offense, which the Armor Master is already lacking. plus, while they'll stack with your normal DR bonus from wearing armor, they won't stack with teh Adamantine Bonus, so in my opinion it would be a waste of at least two feats (Combat expertise and Stalwart Defender).
Beyond that? Boots of Speed or Boots of Striding and Springing. I'd prefer striding and springing personally because you won't benefit from the added effects of haste due to your weapon already having Speed on it. Amulet of Natural Armor is always a solid choice, and anything that can increase your will saves.
