What’s the best weapon for disarming?

Just like the title says. I’m working on a funny build based on disarming (typically suboptimal, yes, but this one’ll be hilarious). What’s the best weapon for this character?

I assume it’ll be a two-handed one, for the +4 bonus. Looking at the SRD, the heavy flail and the ranseur both give an extra +2 bonus, but the heavy flail has just slightly better damage and criticals, so that’s what I’m going with for now.

Is there anything better out there?