Earthshaking Hammer Warrior (3.5e Optimized Character Build)
From D&D Wiki
The idea of this build is to take advantage of the scaling damage of increasing weapon size. At level twenty, you will be using a weapon that does damage as if it were seven sizes large than than medium (3 sizes larger than Colossal)
Races of Stone
Magic of Faerun
Tome of Battle
 Game Rule Components
 Spells, Powers, Soulmelds, Stances, etc...
Enlarge Person, Greater Mighty Wallop(Races of the Dragon), Giant's Stance (Tome of Battle)
A magically treated Gold Goliath Greathammer (magically treated gold is a material in Magic of Faerun, and the Goliath Greathammer is in Races of Stone.)
Race: Goliath (races of stone)
Using a 32 point buy,
STR:16 DEX:15 CON:14 INT:14 WIS:10 CHA:8
Goliath modifiers give us STR:20 DEX:13 CON:14 INT:14 WIS:10 CHA:8
after gaining 5 point increases up to twenty, you will end up with base stats of STR:22 DEX:14 CON:16 INT:14 WIS:10 CHA:8
|Saving Throws||Feats|| Class
|1st||Goliath Level Adjustment||+0||+0||+0||+0||None||None||Muscular build, ability score modifiers|
|2nd||Warblade 1||+1||+2||+0||+0||Exotic Weapon Proficiency(Heavy Goliath Greathammer)||Battle Clarity (reflex saves), Weapon Aptitude||3 Manuevers and 1 stance|
|3rd||Warblade 2||+2||+3||+0||+0||None||Uncanny Dodge||1 Manuever|
|4th||Warblade 3||+3||+3||+1||+1||Weapon Focus(Heavy Goliath Greathammer)||Battle Ardor (Critical confirmation)||1 Manuever|
|5th||Warblade 4||+4||+4||+1||+1||None||None||1 Stance|
|6th||Warblade 5||+5||+4||+1||+1||Quick Draw||Bonus Feat||1 Manuever|
|7th||Warblade 5, Wizard 1||+5||+4||+1||+3||Combat Casting||Summon Familiar, Scibe scroll||Specialize in either transmutation or abjuration, or remain a generalist|
|8th||Warblade 5, Wizard 1, Abjurant Champion 1||+6/+1||+4||+1||+5||None||Abjurant armor, extended abjuration||+1 spell level|
|9th||Warblade 5, Wizard 1, Abjurant Champion 2||+7/+2||+4||+1||+6||None||Swift Abjuration||+1 spell level|
|10th||Warblade 5, Wizard 1, Abjurant Champion 3||+8/+3||+5||+2||+6||Power Attack||None||+1 spell level|
|11th||Warblade 5, Wizard 1, Abjurant Champion 4||+9/+4||+5||+2||+7||None||Arcane Boost||+1 spell level|
|12th||Warblade 5, Wizard 1, Abjurant Champion 5||+10/+5||+5||+2||+7||None||Martial Arcanist||+1 spell level|
|13th||Warblade 6, Wizard 1, Abjurant Champion 5||+11/+6/+1||+6||+3||+8||Improved Critical(Heavy Goliath Greathammer)||Improved uncanny dodge||none|
|14th||Warblade 7, Wizard 1, Abjurant Champion 5||+12/+7/+2||+6||+3||+8||None||Battle Cunning (damage)||1 Manuever|
|15th||Warblade 8, Wizard 1, Abjurant Champion 5||+13/+8/+3||+7||+3||+8||None||None||None|
|16th||Warblade 9, Wizard 1, Abjurant Champion 5||+14/+9/+4||+7||+4||+9||Improved Initiative||Bonus Feat||1 Manuever|
|17th||Warblade 10, Wizard 1, Abjurant Champion 5||+15/+10/+5||+8||+4||+9||None||None||1 Stance|
|18th||Warblade 11, Wizard 1, Abjurant Champion 5||+16/+11/+6/+1||+8||+4||+9||None||Battle Skill (opposed Checks)||1 Manuever|
|19th||Warblade 12, Wizard 1, Abjurant Champion 5||+17/+12/+7/+2||+9||+5||+10||Dodge||None||None|
|20th||Warblade 13, Wizard 1, Abjurant Champion 5||+18/+13/+8/+3||+9||+5||+10||Combat Reflexes||Bonus Feat||1 Manuever|
 Other Components
The spells you take are mostly up to you and your play style, but you MUST take enlarge person, greater mighty wallop, shield, and mage armor. Bull's strength, bear's endurance, haste, heroism ect. are some other good spells you might be interested in.
A Goliath Greathammer starts at 2d6 damage. A goliath can use weapons as if they were one size larger, so we are now at 3d6. enlarge person makes you and any weapon you wield increase by another size, to 4d6. Giant's stance gives you another, so 6d6. But by far the biggest boost is Greater Mighty Wallop, which increases the damage of a touched weapon by one size per 4 caster levels. Martial Arcanist makes your caster level equal to your base attack bonus, so a caster level of 18 gives you 4 size increases, so 6ds goes to 8d6, 12d6, 16d6, and finally 24d6 per hit. And to top it off, the weapon is made of magical gold, which boosts it up another size category, which is technically off the chart (at least the chart that I have available) but following the trend would end up at 36d6 damage, before applying any boosts, manuevers, or other magical effects on you. Diamond Nightmare Blade is especially fun, doing quadruple damage when you hit with it, or 144d6, though it only allows a single attack.
Edit: Hmm, all your info is askewed, im afraid... a medium sized Gold Goliath Greathammer is treated as a large-sized 2handed weapon that deals 2d8. on second hand the standard stone large goliath greathammer does 3d6 (better). this means that a large goliath weapon is better to be made of stone, than be golden and too heavy to use for the goliath in question... golden weapons are terrible all around...
Enlarge Self: no such spell in DnD, Enlarge Person (which im assuming you meant) does not work with goliaths, as they are monstrous humanoids, not humanoids.
Giant's Stance: "......While you are in this stance, you deal damage as if you were one size larger than normal, to a maximum of Large......" Does not stack...
Greater Mighty Wallop: this holds promise...
honestly, a Goliath wizard3/cleric3/mystic thurge8 (ECL 14) can use a huge goliath greatsword with two feats (monkey grip and exotic weapon proficiency; alternatively exotic racial proficiency if you are a goliath but the effect is the same).
now, add in Greater mighty wallop and you can wield a huge goliath greathammer as a colossal goliath greathammer... done... biggest it can get.
i used mystic thurge for both arcane and divine spells... honestly, a 1st level wizard goliath can use a heightened scroll of greater mighty wallop (8th CL minimum) then a scroll of transformation to do the same thing... still...
6d6 at colossal size... not bad. but i can do better.
forget that weapon. minotaur greathammer from mm4 offers a medium sized 1d12 bludgeoning/19-20x4. so a 10% of a crit rather than the normal 5% for a goliath greathammer... same weight too. so the weapon is like 60 lbs. at large, so what? 120 lbs. at huge? thats it.
Assuming you have a strength of 18 + 4 for racial bonuses + 4 from the scroll of transformation. you have a +8 modifier to strength.
1st level Wizard Melee: (Colossal damage) Huge Minotaur Greathammer +7 melee attack (6d6+14 bludgeoning / 19-20x4)
this is the absolute ceiling... with the level 1 goliath wizard... with that mystic thurge 14th level build, however, can take levels in a cleric PrC and feats to make power attack even deal more damage. some rhino armor... now charges deal +2d6 damage...
this is how you power build, using the legit rules.
transformation: You gain a +4 enhancement bonus to Strength, Dexterity, and Constitution, a +4 natural armor bonus to AC, a +5 competence bonus on Fortitude saves, and proficiency with all simple and martial weapons. Your base attack bonus equals your character level (which may give you multiple attacks). You lose your spellcasting ability, including your ability to use spell activation or spell completion magic items, just as if the spells were no longer on your class list.
Depending on interpretation, the bonus of magically treated gold may not stack with mighty wallop, because they both apply to the weapon, likewise with Giant's stance and enlarge person potentionally not stacking, depending on the DM's interpretation.
 DM Counters
Limit the amount the players can increase their weapon damage to collossal size, and/or rule in favor of both of the stacking conflictions above.