I think Zoro moves quicker over a shorter distance than Luffy... He is swift, but Luffy can extend his arms quite fast and pull himself to another location, so he can cover more ground. XD

Of course during gear second.

Well, that is an extra transformation - I'm sure that if Zoro could transform, he would also be faster. But, my point is that Zoro's actions are essentially much swifter than Luffy's normally, Luffy just happens to be able to use his Fruit powers to make himself cover a larger distance than Zoro. I mean, Zoro moved incredibly fast, while he was trying to fight Mr.1 and it was faster than I've ever seen Luffy travel, at least so far (I'm up to episode 332, or whichever one it was that they first met Brook) anyway. XD

Sanji mainly uses his legs to fight. They're probably mutant enough to jump over three buildings!

Heh, you do kind of have a point there. XD. And, LOL, because of the 'mutant legs'. Ahahahahaha!

Definitely Luffy. He has Gear 2nd which can rival Rob Lucci's soru. And he's much faster after the two year time skip, so Luffy is by far the fastest.

Luffy may be faster in gear 2nd but without it Zoro is faster

We have no reason whatsoever to believe Zoro is faster. Besides speed dépends mostly of the legs. Sanji is the one who makes the most sense. Didn't Oda confirm it lately? Sanji, then Luffy, then Zoro.

Uh, I think it's confirmed now after latest chapter! lol

Sorry but those who picked Zoro are biased or delusional.
Wtf Zoro has quick reflexes with swords (arms) that doesn't make him go faster! Where's the logic?
Luffy has gear 2nd and Sanji has superhuman legs.
According to Oda, Chopper in his reindeer form is faster than Zoro...

PS- What's with that stupid picture?