Thus London is more efficient. 
Or shy and scared. Who are you? “We’re NEW and YORK!”
Who are you? “Uh, we’re London”
You point to the only reason New York is leading in the poll. It doesn’t appear to reflect reality, though. Not just on a specially selected metric, but so far on every metric.
Still waiting for the New Yorkers to argue their case. Beginning to accept they don’t have one.
Perhaps it’s my biased opinion but New York seems more culturally diverse.
Just about every nation seems to have some representation.
Also I suspect there are far more Londoners moving to New York than the other way around.
I vote for Rome. The Empire never really fell, it just re-invented itself.
Given that you’ve presented that as an opinion, but one assumes you’ve spent time in both? If so, I find that an extremely odd perspective. My experience is much the same in each. Both are extremely cosmopolitan cities.
Suspicions ain’t evidence! I suspect you have green hair and tusks!
C’mon New Yorkers, you can do better than this! I’m SURE there are stats you guys can cite (despite my arguing otherwise, I don’t actually believe it’s as clear cut as the stats I’ve found - I assume I’m subconsciously selecting to search for things I know London will win on), but nobody’s cited a single one so far; and plenty have been cited in support of London. Where’s that New York spirit?
I am not a New Yorker, but I made the obvious case for New York; that the presence of the United Nations means that New York already is the de facto capital of the world.
I would say that New York is just the new version of York, which is a city in the UK. London is the greatest city in the UK, thus London is greater than York. And since the sequel is never as good as the original …
London > York > New York
You scored a point for New York with that, I’ll agree; and it’s a valid one. But that’s going up against a good dozen points for London so far. I’m sure New York has other points it can score (crap, we need to keep an actual scoreboard!) but they need to be presented.
So far the NY camp is just voting and not backing it up. Which is tantamount to saying “We are the best… but don’t ask us why, ‘cos we got nothin’” This is just conforming by assumption that NY merely tells everyone loudly and repeatedly it’s the best, because it can’t actually prove it, while London is busy actually being the best.
Now, if that emotive taunt doesn’t bring out the New Yorkers with actual evidence, nothing will.
Scoreboard so far (scroll up to see explanations):
London: 9
Financial capital of the world
Most international airport traffic
West End bigger than Broadway
Subway bigger and older
Olympics most times in the world
Tourism most in the world
Home to one of three most famous people in the world
O2 biggest music arena in the world
BBC biggest broadcaster in the world
New York: 1
UN HQ
New Yorkers, bolster than scoreboard! I know you can do it!
Oops. Another point for London.
London 10 / New York 1
This is also true of Tokyo. Tokyo City, Tokyo Prefecture.
I don’t know about the second point, but I doubt it (if there’s a difference either way it’ll be small) but London is extremely, extremely culturally diverse. NYC is either the same or less diverse - I was surprised by how many New York-accented people I met when visiting there, in comparison to London, but that’s only a small point.
NYC is where the aliens all bomb first though.
New York already has a K. London didn’t, but was jealous so tried to add one.
Point: NYC.
The world’s clocks are all based off London (GMT) time. Point London.
I never realized that anyone thought of London that way. How quaint.
London is a country coming down from its trip.
What way? Maybe that’s why NY has lost its position. Its denizens have become complacent, and not noticed they’ve fallen behind in almost every measurable way.
If it were 1911, I’d most definitely vote for London. After all, how many skyscrapers have been destroyed in London with airplanes hijacked by terrorists?
Lonkdon? 
Yeah, isn’t London lucky for not having had terrorist bombings? 