A crit-based AoO build can have fun with Bodyfeeder. A similar PsyWarrior build could have a lot of fun with Mindfeeder.

Overall my favorite is probably Collision. Better than pretty much every other damage enhancement.

Discipline weapons from ToB. Basically a flat +3 attack bonus.

Wounding, though at higher levels is definitely loses its usefulness. Still, TWF wounding weapons can quickly chip into someone's hit points.