the entire list got my vote if u ask me,but if u ask me ill pick 3 players from the list to be the best of each style
ill rate them base on their technique:-

Ronaldo - power, dipping ball, accuracy (gets through the wall,its for sure a trouble for the keeper)
Carlos - one hit wonder + wicked outswing
RvP - classic style, accuracy(curl+placing),with extra power (IMO, his balls travel alot more faster then the others,making it quite unstoppable) 1 of the best left footer otherwise the best

others are brilliant as well,well most of them in the list probably 80% or more has the typical classic placing freekicks
the above are my 3 best

but if we talk about proven best
it gotta be Beckham
how many goals have he scored under freekicks?
is there any webbie we can track such records

i wanted to mention this name as well
the famous GK that comes up to take freekicks and penalty kicks

anyway,its quite unfair to rate players that are retired to players that havent
its like ure taking a Handphone made 10 years ago comparing it with the latest nokia hp today.
zidane,figo,carlos all..shouldnt be in the list
beckham prime time is over(but has achieved his name in freekicks,so as for the other players in the list up there),its also unfair to rate old players with prime time players
del piero all already ah pek(despite an ah pek,he still can kick butts), cant compare with a ronaldo in his early 20's