Get a reach weapon, combat reflexes, and Hold the Line (CW). Pair up with Dodge, Mobility, and Elusive Target. Finish off with Robilar's Gambit to produce a "standard" AoO based build.

They charge, you get an AoO for them charging. Activate Dodge and Robilar's Gambit (you need to have an action for these, which an AoO grants). Elusive Target negates all that power attack bonus damage, which is the real threat, not merely the strength. It'll hurt a lot less, and every swing they take, you get to take one back. Works best with a mix of Fighter (for the feats, this one's pretty hungry) and Shadow Hand, for a dex-based build.

If you get to go first (high dex, remember!), then you can ready an attack vs. charges - using a longspear or ranseur means double damage on that attack.

For extra bonus rules lawyering, point out that Elusive Target specifically calls out that they take "Their normal penalty on attack rolls", despite losing the Power Attack bonus. Insist that this means they either can't take the penalty off their AC, or that they take penalties to both.