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.