User blog comment:ARZC/Luffy vs Law/@comment-4754162-20120530011748

Judging from what we've seen, I'd go for Luffy. Law needs to deploy his room in order for him to be able to do something/anything. Luffy should be able to stay ahead of Law with his speed and kenbunshoku haki.

For that matter, even if Law was able to deploy his room, it can still be negated by enough bushoshoku haki (Law cuts Tashigi and her sword cleanly into half but Law was not able to cut through Smoker's jutte - assumed to be embeded with haki, and both happened inside of his room).

Someone mentioned Zoro, I agree. Zoro (provided having enough level of haki embeded into his swords) should be able to fight Law one on one and win it.