For a fairly simple build, a totemist (Magic of Incarnum)//crusader (Tome of Battle) with the Stone Power and Martial Study (Iron Heart Surge) feats could be pretty tough - a character with all good saves, full BAB, d10 HD, full plate armor, healing every round (while attacking) (assorted crusader maneuvers), bonus temporary hit points every round (while attacking) (Stone Power), the ability to remove negative effects from yourself (iron heart surge), and all the bonuses you can get with soulmelds, like evasion (great raptor mask) and short-range dimension door at will as a spell-like ability (blink shirt).
Edit: For some reason the thought really stuck with me, so I made a sample guy. Stats using the elite array, and no magic items added yet. I ended up leaving out Iron Heart Surge because of being a warforged, but it would be an obvious pick otherwise for Survival Guy.
Also, you can reallocate essentia each round, so you could have 3 in great raptor mask outside of combat (and have +8 to Spot all the time), and then shift it into speed and AC bonuses once combat starts instead.
NG male personality warforged crusader 6//totemist 6
Medium construct (living construct)
Init +1; Senses Listen -1, Spot +1
Languages Common
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AC 27, touch 11, flat-footed 26
(+1 Dex, +4 natural armor +8 armor, +4 tower shield)
hp 51 (6 HD); can't be healed by conjuration (healing) spells; steely resolve 10; DR 2/adamantine
Immune poison, sleep effects, paralysis, disease, nausea, fatigue, exhaustion, effects that cause the sickened condition, energy drain, sneak attacks, critical hits
Fort +8, Ref +6, Will +4; evasion, indomitable soul, totem's protection, zealous surge
Weakness vulnerability to rusting grasp (2d6 damage)
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Speed 30 ft.
Melee longsword +8 (1d8+2) or
Melee slam +8 (1d4+2)
Space 5 ft.; Reach 5 ft.
Base Atk +6; Grp +8
Atk Options furious counterstrike, smite 1/day (+0 attack, +6 damage)
Special Actions wild empathy +6 (+2 magical beasts)
Maneuvers Known (IL 6th):
1st—charging minotaur (your bull rush charge also does 2d6+2 damage if successful), crusader's strike (on successful attack, heal you or an ally within 10 feet 1d6+5), leading the attack (on successful attack, your allies get +4 to attack your target until your next turn), stone bones (on successful attack, you have DR 5/adamantine until your next turn), vanguard strike (on successful attack, your allies get +4 to attack your target until your next turn)
2nd—foehammer (one attack ignores DR and does +2d6 damage), mountain hammer (one attack ignores DR and hardness and does +2d6 damage)
Stances Known (IL 6th):
1st—bolstering voice (all allies within 60 feet who can hear you get +2 morale on Will, or +4 vs fear), martial spirit (each successful melee attack you make heals you or an ally within 30 feet 2 damage)
Soulmelds Shaped (ML 6th; essentia capacity 2; 4 essentia):
Feet—worg pelt [2 ess] (+2 +2/essentia Hide and Move silently; +5 +5/essentia speed)
Totem (ML 7th; essentia capacity 3)—great raptor mask [0 ess] (evasion; +2 +2/essentia competence on Spot)
Unbound—blink shirt [0 ess] (pseudo-dimension door at will, range 10 ft + 10 ft/essentia), wormtail belt [2 ess] (+2 +1/essential natural armor enhancement)
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Abilities Str 14, Dex 13, Con 17, Int 8, Wis 8, Cha 10
Feats Adamantine Body, Improved Fortification, Stone Power
Skills Whatever, but Listen and Spot are the most important.
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Furious Counterstrike (Ex) Get a bonus to attack and damage based on your steely resolve pool
Indomitable Soul (Ex) +Cha to Will saves
Steely Resolve (Ex) Delay up to 10 damage you take until the end of your next turn
Totem's Protection (Ex) +4 on saves against the supernatural abilities of magical beasts.
Zealous Surge (Ex) 1/day, you can reroll a save