My pick is Dave Paris...the word fraud dodgy and brown envelope comes to mind...hes a ref who as taken a few George GRahams in his time.
Joe Cortez is on the slide, but he's still quality. Micky Vann is awful and he gets my vote because of his horrendous scorecard for Chavez-Whitaker where he inexplicably deducted a point from Whitaker when Whitaker wasn't penalized. He's a generably bad referee anyhow. Terry O'Conner needs to be on the poll. I remember Ortega had a bad call in Calzaghe vs. Kessler, but other than that he seems competent. Kenny Bayless for a while was the best in the business with a flawless record, but it seems like he's been missing a few calls here and there lately.
Puerto Rican refs have been very unfair when arbitrating fights in "La isla" ( The Island ). Not to say that the Boricua fighter benefiting from the early stoppages and bad calls wouldn't of won without the ref, just sayin very biased stuff. ie, Cotto v Corley.