I find it interesting that while everyone on the island calls the big guy "Hurley," Locke calls him "Hugo." The big guy told Jack in an earlier episode (Raised By Another) that Hurley is just a nickname and tells him his real name, but I don't recall him ever telling anyone else. And Jack isn't the type to divulge anyone's secrets. Sawyer, while reading the messages to be sent on the raft with them (Exodus Part 1), reads that someone on the island is leaving his millions of dollars to his mom. "Who is Hugo?" he asks.
Did I miss something? Locke keeps saying "Hugo" and Hurley hasn't said, "Dude, how do you know my name?" How does Locke know Hurley's real name? Maybe it's a clue that Locke knows who Hurley was because Hurley owns the box company where Locke worked.