Smoker

[Godgrave]

Shit, this guy's not only cool, but he's also uber powerful!

Luffy was shitting bricks those first few moments when he started battling him in Loguetown (I think) ... I haven't read the manga, so I dunno if he gets to battle him again or in the series (come only till 85 in the Baraque Works arc).

Could he be an adversary Luffy couldn't beat so far in the series, provided nobody interrupted his fight?

[Ladywriter]

to win against Smoker ya gotta hit him, not an easy thing to do to a guy that can turn into a puff of smoke o.0

[Sledgstone]

Could he be an adversary Luffy couldn't beat so far in the series, provided nobody interrupted his fight?

at that point in the series, theres no way luffy could have beaten him unless he use'd smoker's own weapon against him.. logia types are crazily powerful.